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Important Note: The author: Vincent Pardieu is an employee of GIA (Gemological Institute of America) Laboratory Bangkok since Dec 2008. Any views expressed on this website - and in particular any views expressed by Vincent Pardieu - are the authors' opinions and do not necessarily reflect the opinions of GIA or GIA Laboratory Bangkok . GIA takes no responsibility and assumes no liability for any content on this website nor is GIA liable for any mistakes or omissions you may encounter. GIA is in particular not screening, editing or monitoring the content on this website and has no possibility to remove, screen or edit any content.


About FieldGemology. org

This website is home for "Shameless Travel Addicted Gemologist" Vincent Pardieu (B.Sc., GGA, G.G.). Vincent is "Supervisor, Field Gemology" at GIA Laboratory Bangkok. He is a gemologist specialized on "origin determination of gemstones".
This is also home for Vincent's regular traveling companions: David Bright, Jean Baptiste Senoble, Richard W. Hughes, Guillaume Soubiraa, Walter Balmer, Michael Rogers, Kham Vannaxay and many others like recently: Philippe Ressigeac, Oliver Segura , Flavie Isatelle and Lou Pierre Bryl.

We are gemologists (gemmologists) sharing a passion for gemstones, gemolology (gemmology), gem people and traveling.

You will find in this website gemological expedition reports and some studies of gemological interest.

Visiting many gem mining areas we saw that people in remote mining and trading areas have difficulties to access to gemological publications. As today the Internet can be accessed in most of these gem mining areas and trading centers, the author started to build this website to give gem people living there the opportunity to see the result of the gemological expeditions they were associated in. It is a way to thanks them for their time and collaboration and to help them to get access to more gemological information.

At the same time the author hope that these expedition reports will please the people from consuming countries interested in gemstones and fascinated by their mysterious origins. Our purpose here is to help people facing difficulties to get quality first hand information about gems and their origins to get the information they need through this website and its links.

With our field expeditions to gemstone mines and gem markets around the world, we intend also here to share our passion for photography, gems and our fascination for the work of the "Gem People" bringing gemstones from the ground to magnificent jewelry.

From the gems external beauty to the intimate beauty of gemstone inclusions, from gem lore to the mines, the people and the landscapes gems origin from, we expect to share with you our passion for gemstone beauty.

We also invite you to join us on some gemological forums we are active in as they are convenient tools to get rapid answers to your questions as they are regularly visited by many other passionate gemologists, jewelers, hobbyists and professionals willing to learn more and share their knowledge about gemstones.


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Popular Articles

"Tsavorite, an Untamed Gem" with R.W.Hughes, first published in ICA's InColor (Winter 2008)
"Working the blue seam" The Tanzanite mines of Merelani with R.W.Hughes first published on
"Spinel, the resurection of a Classic" with R.W. Hughes, first published in ICA's InColor (Summer 2008)

Gemological studies

(Apr. 2009) "Sapphires reportedly from Batakundi / Basil area" a preliminary study about unusual sapphires we saw at GIA Laboratory Bangkok
(Mar. 2009) "Rubies from Niassa province, Mozambique" a preliminary study about rubies we saw at GIA Laboratory Bangkok
"Lead glass filled rubies" :
First published on AIGS Lab Website (Feb 2005)

Expedition Reports

Autumn. 2009: GIA Field Expedition FE09: Rubies from Mozambique. (pdf file)

May. 2009: GIA Field Expedition FE08: Melos and their pearls in Vietnam. (pdf file)

Dec. 2008 and Feb-Mar. 2009: GIA Field Expeditions FE01 and FE04: Rubies and sapphires from Pailin, Cambodia. (pdf file)

Aug. 2008: Sapphires and Tsavorite from the south of Madagascar with the AFG (Association francaise de Gemmologie) : Available soon...

Apr. 2008: Expedition to the new Winza ruby deposit in central Tanzania with Jean Baptiste Senoble and the support of the Gubelin Gem Lab

October 2007: Gemological expedition to East Africa (Kenya and Tanzania) with Richard W. Hughes, Mike Rogers, Guillaume Soubiraa, Warne and Monty Chitty and Philippe Bruno:

Summer 2006: Expeditions to Central Asia gem wealth with Guillaume Soubiraa and the support of the AIGS, the ICA and the Gubelin Gem Lab:

Oct. 2005: Colombia by J.B. Senoble

Sep. 2005: Madagascar with Richard W. Hughes and Dana Schorr (Will be available one of these days...)

Summer 2005: Gemological expeditions to South East Asia (Vietnam) South Asia (Sri Lanka) and East Africa (Kenya, Madagascar and Tanzania) with J.B. Senoble and Tanguy Lagache with the support of the AIGS, the ICA and the Gubelin Gem Lab:

- Feb. 2005: A visit to Thailand, Cambodia with the AFG (Association Francaise de Gemmologie) (under construction)

- 2002-2007: Expeditions to Pailin (Cambodia), Chanthaburi Kanchanaburi (Thailand) Houay Xai (Laos) Mogok, Namya (Burma) (under construction)

- 2001: Expeditions to Namya, Hpakant and then Mogok with Ted and Angelo Themelis and Hemi Englisher (under construction)

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The Winza ruby and Sapphire mining area,
Mpwapwa district, Dodoma province, Tanzania

( This page was first published on Feb 12th 2009 )


Text by Vincent Pardieu
(formerly and at the time of the expedition, gemologist at Gubelin Gem Lab, Lucerne, Switzerland,
and field gemologist for GIA Laboratory Bangkok when this page and the Winza article were published.)

Photos by Vincent Pardieu,
Jean Baptiste Senoble (Nomad's, Bangkok, Thailand)

Rubies and sapphires from Winza, Tanzania:
Here are two beautiful faceted Winza rubies (over 5 cts for the smaller one and over 10 carats for the larger) associated with some rough, crystal specimens and also some Winza sapphires in their amphibole matrix associated with orange garnets...
Stones courtesy: Van Cleef and Arpels/Piat/Swala Gem Traders, Photo:V.Pardieu/Gubelin Gem Lab, 2008


This expedition was the subject of "Rubies and Sapphires from Winza, Central Tanzania." an article by Schwarz D., Saul J.M., Schmetzer K., Laurs B.M., Giuliani G., Klemm L., Malsy A.-K, Erel E., Hauzenberger C., Du Toit G., Fallick A.E., Ohnenstetter D. and Pardieu V., published in Gems & Gemology, Vol. 44, No. 4, Winter 2008, pp. 322-347

This expedition was the subject of "An expedition to Tanzania's new ruby deposit in Winza" by Jean Baptiste Senoble, published in ICA's InColor magazine, Spring 2008 issue.

This expedition was co-financed by the Gubelin Gem Lab located in Luzern, Switzerland (where Vincent Pardieu was working as gemologist at the time of the expedition) and by Jean Baptiste Senoble, a Thailand based French gemologist whihc was also a member of this expedition.

1) Introduction:

"In November 2007, rubies of high quality and pure red to pinkish-red colour were found near the village of Winza, (Mpwapwa district), in the Dodoma region of Tanzania, and quickly attracted attention outside Tanzania - most recently at the BaselWorld show (in April 2008). The superior quality of these rubies and sapphires is characterised by outstanding transparency..." ( text from the Gubelin Gem Lab Newsletter n22 published on May 05, 2008)


( A very fine quality Winza ruby, reminding the beauty of Thai rubies as seen during the BaselWorld show.

This gem was unheated and about 3 carats. Stone courtesy Gemburi, Photo: V.Pardieu, 2008 )


Obviously when such exceptional gems appear in the market for a gemologist specialized on origin determination of gemstones, a visit to the new mining area makes a lot of sense. I decided, with the support of the Gubelin Gem Lab, I was then working for, to visit this new deposit few days after the end of the BaselWorld show at the end of April 2008. Jean Baptiste Senoble, an enthusiastic young French gemologist and gem lover who used to travel with me in Tanzania in 2005 joined me on this expedition. The purpose of this expedition was to collect first hand data and samples in order to maintain the Gubelin Gem Lab gemstone reference collection up to date and to collect first hand data about gem mining and trading in Winza for future articles and presentations on these stones.

This specific April 2008 expedition was facilitated by the fact that in August 2005 and October 2007, the author did two very complete surveys of the gemstone mining areas in Kenya and Tanzania (see following map) with Tanzanian gem broker Abdul Y.Msellem as guide and with the support of Eric Saul (ICA Ambassador to Tanzania) and his brother Mark from Swala Gem Traders in Arusha, which are licensed gem miners and dealers in Tanzania. These expeditions were very useful to collect, of course, additional samples and data from known gem sources but also to build and maintain a strong local network (with Tanzanian gems dealers, brokers, miners, mining officers and technicians) which turned to be very useful and reliable for the Winza case.

In fact it was Abdul Y.Msellem (Photo on the right, presenting a large Winza sapphire crystal specimen he mined in December 2007), who was our guide for the previous two expeditions to Tanzania who first informed me about the new deposit at Winza at the end of November 2007. Abdul then left to spend December 2007 at Winza in order to mine.
After his return from the area, in January 2008, he confirmed to me that fine rubies were mined there and he gave me by SMS the first description of the new mining area. These informations which were then confirmed during our visit at the mines.

In April 2008 with the support of the Saul family and Abdul Y.Msellem, I was happy to lead for the Gubelin Gem Lab a short field expedition to visit the new Winza ruby mining area.

From April 15 to 22, 2008, with the support of our Tanzanian friends and from the Tanzanian local authorities we succeeded to reach the new mining area where we stayed 3 days at 2 nights in order to witness and document the mining activity. We also visited the gem markets of Mpwapwa and Arusha.

About 2 weeks after the author and Jean Baptiste Senoble visit of the Winza mining area, in May 2008, GIA gemologists: James E. Shigley (Distinguished Research Fellow, GIA Research) and Brendan M. Laurs (Editor, Gems & Gemology ) also succeded to visit Winza in order to document the location, the geology, and the mining of the new ruby and sapphire deposit. They were accompanied by gem dealer Dimitri Mantheakis (Ruvu Gemstone Mining Ltd., Dar es Salaam ), who arranged the logistics and helped them to obtain the necessary permissions for that visit, and by several government officials for their security.


James E. Shigley (Distinguished Research Fellow, GIA Research) and Brendan M. Laurs (Editor, Gems & Gemology) visiting Winza, Tanzania in May 2008


Visiting both the mining area at Mtakanini and the Mpwapwa gem trading centre, they were also able to purchase a selection of Winza material for GIA ongoing research project on gem corundum with the help of Mr. Mantheakis, and the Tanzanian official which were traveling with them.

After these two expeditions, the Gubelin Gem Lab, the GIA and other researchers decided to collaborate to produce a common article about "Rubies and Sapphires from Winza, Central Tanzania" by Schwarz D, Saul J.M., Schmetzer K., Laurs B.M., Giuliani G., Klemm L., Malsy A.-K, Erel E., Hauzenberger C., Du Toit G., Fallick A.E., Ohnenstetter D. and Pardieu V. in Gems & Gemology, Vol. 44, No. 4, Winter 2008, pp. 322-347.

Besides the article, some addtional photos taken during the 2 expeditions by the Gubelin Gem Lab and GIA and some additional inclusion photos of Winza gems are also available on G&G Data Depository on GIA website.

This page will now focus on the expedition I lead with the support of Jean Baptiste Senoble and the Gubelin Gem Lab and on the inclusions found in the rubies and sapphires collected during that expedition.

2) Historical background of the Winza ruby and sapphire mining area, Tanzania:

Tanzania is the East African country with the oldest gemstone mining traditions: Rubies were found near Longido few years before the First World War when the country was under German domination as Tanganika (from 1885 to 1918). Other discoveries will follow during the XX century under the British rule (from 1918 to Dec 9, 1961) like near Umba in the 1950's and after the independence like in Matombo and Mahenge areas of the Morogoro province during the 70's and 80's and later during the 90's near Songea and Tunduru.
The most recent ruby find took place in 2007 near Winza village, Mpwapwa district of the Dodoma province and this is what this page is all about:

At Longido and in other similar Tanzania rubies producing localities like Lossogonoi, rubies are found following a “reef” of “anyolite” a rock composed of green zoizite and dark green to black amphibole. If Longido is still nowadays an active mining area, ruby mining at Lossogonoi stopped in 2006.
In the 1950's rubies were again discovered near the Kenyan border in the Umba river valley from a pegmatite intruding into serpentinite. The AAPS (Africa-Asia Precious Stones and Mining Co.) company who started to work the deposit in 1989 stopped its activities in 2006 (A. Msellem, Pers. Comm., Oct 2007).
During the 1970's the central Morogoro region become also known as a ruby producer with two main production areas where rubies and spinels are found associated with marbles in placers or in situ: The first area is located in the east of Morogoro town near the village of Matombo, the area produced mainly during the 1980's when Thai companies were working the deposit but after the discoveries of rubies in Luc Yen and Quy Chau (Vietnam) and Mong Hsu (Burma) ruby mining activities in Morogoro decreased and after the discovery of ruby and sapphire in the south of Tanzania (Songea 1992, Tunduru 1994) most miners left Matombo (A. Msellem, Pers. Comm.). Ruby and spinel mining was only residual when I visited the area in 2005 and was reported to have completely stopped during his recent visit in Oct 2007 (Morogoro mining officer, Pers. Comm., Oct 2007)
The second ruby mining area in Morogoro province is located in the south of the province near the mountain city of Mahenge. The Mahenge mining area includes the following mining areas: Lukande, Mayote, Chipa, Epanko, Mbarabanga, Kitonga and Kitwaro). The Lukande, Mayote, Chipa areas are not anymore as active as during the 1980's when several Thai important mining operations where working in the area. Nevertheless during our visits in 2005, and 2007 we could see that several hundred miners were still mining rubies mainly near Lukande. Walter Balmer, a Swiss gemologist who visited Mayote and Chipa in June 2007, told me that some small groups were also still working these areas. In the early 2000's the focus seems to have moved mainly from ruby to spinel and the Epanko area became the main mining area around Mahenge. It was famous to have produced in August 2007 several giant spinel crystals from which beautiful large size red spinels were cut.
In the southern part of Tanzania rubies were also found near Songea (1992) and Tunduru (1994). In the rivers around Tunduru rubies are found in small sizes from alluvial placers in association with sapphires (blue, yellow, violet), spinels, chrysoberyl (including alexandrite), garnets (including tsavorite), diamond, and many other gems.

Besides some exceptional stones mined mainly from the different Morogoro deposits, Tanzania was until recently mainly known to produce cabochon or heat treatment quality rubies. Nevertheless in November 2007 the word was in the Tanzanian gem trade that fine quality rubies were found near the village of Winza in Mpwapwa province of the Dodoma region.
Tanzanian gem broker Abdul Msellem and 600 other miners and brokers from different mining deposits and gem markets moved to work the new deposit in December 2007. In January, back in Arusha, the main Tanzanian gem trading center, he informed me of the new deposit. When in April 2008 Vincent Pardieu and Jean Baptiste Senoble and in May 2008 James Shigley Brendan Laurs, visited the area in two different expeditions, about 5000 miners where working the area.
In July 2008 (A. Msellem, private comm.) reported that the number of buyers was still increasing with more than 100 foreign buyers in Mpwapwa and about 6000 miners.

The way rubies were discovered in Winza is still unclear and remains subject to speculations: Nevertheless thanks to Swiss gemologist Walter Balmer, I was able to get in January 2009 a document by J.K. Whittingham: "The geology of the Nyanzwa area" (1954). In this document a very short reference is made on page 25 about "ruby mica" mining at Winza by the "Tchenzema Syndicate Limited" which in 1926 and for about 2 years was reported to have mined "ruby mica". (See geology chapter for more details) If the term ruby is used here, it seems that the term "ruby mica" was commonly used used in the past to describe many minerals and thus it is possible that the Tchenzema Syndicate Limited never mined any ruby (the red gem variety of mineral corundum) in Winza but some reddish mica instead... (John Saul, 2009, Pers. Comm.). Geologist John Saul, a well known expert of East African gems and geology and the father of Mark and Eric Saul, provided me recently another interesting document of the same period: "Notes for Mica Prospectors in Tanganyika" by Sampson, 1954 in which "ruby mica" is clearly describe as a trade name for some types of mica. John Saul also told me also in April 2008 while I met him on my return from Winza that he saw in the 1960s some low quality corundum reported to have been mined somewhere near Mpwapwa (J.Saul: Pers. comm., 2008).Other sources are going in a similar direction: A map from Geological survey of Tanzania (1982) presented by E. Malisa and S. Muhongo in 1990 in "Tectonic setting of Gemstone Mineralization in the Proterozoic Metamorphic Terrane of the Mozambique Belt in Tanzania" was provided to me by Walter Balmer descibing Mpwapwa area as a known gemstone producing area in 1982 without presenting any details about the nature of the gems mined there.

In Mpwapwa police chief office on an old Mpwapwa district map published during the British colonial times, I noticed mining symbols near the location of the current ruby find and another is visible for an area on the other side of the river reported to produce garnet (see map later in the report). This find was the start of my historical research but it seems that these mining symbols are indicating the former Winza mica mines described by Whittingham.

Nevertheless if some additional bibliographic research might one day reveal that Winza rubies were known and possibly mined in the past before to be forgotten by most people. The fact is that the modern history of the Winza mines clearly started in 2007: On April 19th 2008, while having diner in Mpwapwa, local people told me that a villager from Winza was mining for many years the area in secret and traveled regularly to Dar Es Salaam to sell his stones. As the man passed away his son tried to continue his business but he was followed and soon many people started to come to Winza to mine and trade rubies. Probably this man was aware one way or another of ruby mining in 1926 or may be also during the 1950s.

Abdul Y. Msellem confirmed to me that story and recently he provided to me additional details:

"The modern history of Winza rubies and sapphires started during the 1990's as an old man from the Winza village, who passed away recently, went regularly to his farm located at “Mtakanini” in Winza forest to dig for gems. Returning at Winza village he used to sell what he got there to an old “Somali man”, who also died recently, this Somali was regularly traveling to Dar es Salaam , Nairobi and Mombasa for trading. The old villager called his son: Mr. Shabani just before to die. Mr. Shabani which was then working as a watchman at Dar es Salaam returned home and got the secret of the location of the gem deposit at their farm in Mtakanini forest. Mr. Shabani started then to go to the “Mtakanini” farm, in order to mine rubies. In October 2007 he was selling gems to Thais and Sri Lankan gem dealers in Dar es Salaam . People followed him and rapidly many miners arrived at Winza.

When Abdul Y. Msellem arrived at Winza on Dec 07th 2007; he registered as no.71 on the guests register papers of the mining village secretary. With the other new comers he was then introduced to the Kibakwe and Winza village leaders and to the local miners. During that meeting they were also introduced officially that the founder of the “Winza Mtakanini” mining area was Mr. Shabani. Mr. Shabani which was then also mining at Mtakanini then stood in front of the new miners and welcomed them."

The Winza modern mining history started then in November 2007 when the word about the existence of rubies in Winza spread in the market. By the end of January Tanzanian gem broker and miner Abdul Y. Msellem reported to me that about 600 miners moved to this area. At the time of the expedition I had with Jean Baptiste Senoble in April 2008 and then of James Shigley and Brendan Laurs in May 2008 about 5000 people were living and working there.

3) Find the the Winza ruby and sapphire deposit using Google Earth:

We invite you to follow our April 2008 fieldtrip to the new Tanzanian ruby deposit nearWinza using the potential given by the free software Google Earth. Just download and install the software, then using our links you can get a better idea about the mining areas we visited or those for which information is available in the gemological litterature. We recommend you to select the "terrain" option (down left in the "layer" booklet) in order to enjoy a 3D visit.

Using our Google Earth placemarks, you can now follow our expedition and "fly to Winza" downloading the placemarks we prepared.
Just download them clicking on the icon on the left to fly to Winza!

4) Geology:

Regarding the local and regional geology of the Winza deposit,a first step was to study geological maps associated with the probable latitude and longitude of the deposit. Using the GPS data collected during the expedition to Winza with my GPS we could get some first information about the area geological context. Then field observations and the study of samples collected on site helped geologists John Saul and Gaston Giuliani to provide additional information regarding the geology of the Winza rubies sapphires for the article "Rubies and Sapphires from Winza, Central Tanzania." by Schwarz D., Saul J.M., Schmetzer K., Laurs B.M., Giuliani G., Klemm L., Malsy A.-K, Erel E., Hauzenberger C., Du Toit G., Fallick A.E., Ohnenstetter D. and Pardieu V. in Gems & Gemology, Vol. 44, No. 4, Winter 2008, pp. 322-347.

We can say to summarize the information available in this article that the rubies and sapphires from Winza are hosted in metamorphic rocks from the Usagaran Belt. The presence of both rubies and sapphires with different morphologies could be explained by the presence of two different generations formed at different geologic times under locally different conditions of temperature and pressure. (For more details please see "Rubies and Sapphires from Winza, Central Tanzania"by Schwarz&al Gems & Gemology, Winter 2008, Vol. 44, No. 4, pp. 332)

GPS Data about Winza gem mining area:
Mining Area: 07° 05'03"S 36°19'11"E;
Mining Camp (Police camp): 07° 04'58"S 36°19'14"E;
Winza Village: 07° 00'58"S 36°21'54"E

Walter Balmer, a former gemmologist of the Gubelin Gem Lab, working currently on a Ph.D. at Chulalongkorn University in Thailand regarding the geology of gem deposits in East Africa and visited Tanzania in 2007 provided me also several interesting geological maps and informations:…

The Usagaran Belt is part of a precambrian basement. The paragneisses and metapelites found in this area represent very old sedimentary rocks (>2.0Ga) of reworked and metamorphosed craton material.” (Walter Balmer, Pers. Comm, Jul. 2008)

Using that recent map and the GPS Data collected in the field, we can see that the mine is located within the Usagaran Belt. "The Usagaran Belt is formed basically by a metamorphosed sedimentary basement and a significantly younger magmatic cover. The basement consists mainly of reworked craton material including paragneisses and metapelites. Metagabbros, metabasalts as well as migmatic orthogneisses are also found in the basement. " (Walter Balmer, Pers. Comm, Jul. 2008)

On a second interesting recent geological map whihc was provided to me by Yves Deschamps from the BRGM:
(Y. Deschamps, et al. (2004): "Geology and Gemstones Deposits of East Africa", map scale 1:4'000'000, BRGM) :
I've reported Winza and some other important gem mining areas in Tanzania: It is interesting as we can see here the localization of the Tanzanian main gem deposits located in the Mozambique belt, on the east of the Tanzania craton.
Winza mining area is indicated in this map to lay within the Palaeoproterozoic unit PP1-3 which includes meta-sediments, orthogneisses, granulites, metagabbros, marbles & ecologite lenses. This cover a lot of things and is not here much helpful to describe the deposit but it is understandable as with the map scale at 1:4'000'000 the information is more on a sub-continent level rather than regional level.


Swiss gemologist Walter Balmer provided me also in January 2009 a third geological map and a very interesting report by J.K. Whittingham, (Map scale of 1:125’000), from "The Geology of the Nyanzwa Area", Quarter Degree Sheet 63NW, Geological Survey of Tanganyika, 1954 ). Sadly we got this document too late for the different articles published in InColor, Rapaport and Gems and Gemology.

I reported on this detailed old geological map the location of the mining camp and the mines:
The mining area is located, and this is probably very interesting, exactly lithological boundary. The pink area on the east of the boundary is reported as kyanite-garnet-biotite-gneiss while the thin pink area on the left of the boundary is reported as biotite-gneiss and amphibolite. .

The study of "The Geology of the Nyanzwa Area", Quarter Degree Sheet 63NW, Geological Survey of Tanganyika, 1954 by J.K.Whittingham is also very interesting as it is describing the Mangalisa and Winza area providing also some interesting historical background and this is to my knowledge the possible earliest reference about the presence of "ruby" near Winza, nevertheless the term used is "ruby mica" used could in fact mean something very different from Winza ruby: "ruby mica " is a disused term formerly used for goethite, lepidocrocite, fine quality Indian mica, reddish mica, etc.. The term is then difficult to use as it has been applied differently to diverse substances (John Saul, 2009, Pers. Comm.) and probably in this case just refer to a trade name for some qualites of mica.
Pages 2 and 3: "During the German administration (of Tanganika) several explorers, notably Von Prittwitz und Gaffon (1932) in 1899 and Tiller (1913) in 1911, traversed the Nyanzwa area... When Tiller (1913) traversed the North-Eastern part of the area in 1911, copper and mica had already been discovered and trenched near Winza... Page 25: "Mica prospecting has been carried out in the Mangalisa area since the time of the German administration (Tiller 1913) when prospects on the western escarpment near Winza and Mkofwa were exploited. About 1926, Tchenzema Syndicate Limited produced ruby mica at Winza for about two years, then it was abandoned until 1934 when mica pegmatites at Winza, Lutalawe and Mkofwa were worked by Schultz, Nuffer and Theoren (Williams and Skerl, 1940, pp17-18)"

The author also describe alluvial garnet deposits on the east side of Yalumba mountain and report that beryl was discovered by Wessels in the mica pegmatites of Mangalisa, kyanite is reported also to occurs commonly in the semi pelitic rocks of Mangalisa as well as copper and manganese.
The garnet alluvial deposit is probably the old mines reported by Abdul Y.Msellem and the local Mtakanini miners to be on the western side of the Mtindiri River, while the mica mines are probably the old mines reported on the Whittingham map and the map we saw at Mpwapwa police station.

5) On the way to Winza:

Jean Baptiste Senoble, a French gemologist who visited already Tanzania with me in 2005 and myself arrived in Arusha, Tanzania on April 15th 2008. Our plan was to be back in Europe on April 22 2008. A six days expedition sounds a little short to visit a new mining area, but the fact was that thanks to the help of our local contacts in Tanzania everything was ready when we landed in Tanzania.
Our expedition started in Arusha, which is with Dar Es Salaam (Tanzania) and Nairobi (Kenya) one of the most active East African gem trading centre.

Our visit to Tanzania would not be succesful without the support of the Saul brothers: Mark and Eric from swalagemtraders. Based in Arusha, they were great supports for all our expeditions: Mark and Eric Saul are the two sons of John Saul, the famous American geologist which name is commonly associated with the history of gem discoveries in East Africa. While Mark is most of the time staying in the Tanzania, Eric, the current ICA Ambassador to Tanzania, is traveling back and forth between Arusha and the rest of the world. Each visit in Tanzania starts for me with a visit to Mark Saul buying office or to the Swalagemtrader's retail shop at the Arusha hotel. It is then a good occasion to check interesting gem parcels (like here Winza rubies, Loliondo spessartine garnets and Lemshuko tsavorite...) and collect fresh news about what's happening in the country.

The second step of a successful visit to Tanzania is for me to meet my friend Abdul Msellem (left on the photo) a friendly Tanzanian gem broker and miner which travelled with me as a guide/translator all over Tanzania already in 2005 and 2007. His knowledge about the Tanzanian gem trade and communication skills were all the time very useful to explain to the local miners and dealers what our intentions were and to get their support for our expeditions. Abdul father was himself a gem dealer; it explains Abdul incredible knowledge about the history and the inside of Tanzanian gem trade.
Regarding the present expedition, Abdul Msellem support was of great value as he was the first to inform me about a possible new mining area in Tanzania in November 2007. Then after his return from the mining area at the end of January 2008, he confirmed to me the new discovery near Winza village and provided me a first description of the gem discovered there. This discovery was then confirmed to me by Eric Saul and I announced the new discovery on GemologyOnline forum on Feb 05 2008.
Abdul was mining there for one month from the end of December to the end of January. His first hand information and knowledge of the mining area were of course very valuable for us to prepare our expedition. Here on April 16, the day after our arrival in Arusha, Abdul took Jean Baptiste Senoble and I to the local Arusha gem market in order to meet Mr.Sadalla "aka.Kujuku" (with the cap) a local gem dealer I met already in 2005 while he was working in Songea. Mr.Sadalla "aka.Kujuku" was just back from Winza and was fine to show us what he collected there. It was a good opportunity to get a first idea about what was produced there and get additional fresh information about what was going on there...
Jean Baptiste Senoble studying a Winza ruby and sapphire parcel in Arusha on April 15th 2008 while gem broker Jones Mwakabuku is speaking on the phone. Motorbikes and cell phones are the two best friends of the typical Tanzanian gem broker. On the following photo: A close view on the ruby and sapphire parcel enable to have a good idea about the Winza rubies and sapphire production color range: Besides the very thought about red rubies which have stunned by their quality the world gem market at the BASELWORLD fair in March - April 2008, red-pink, pink, blue, purple pink, purple blue, are also commonly found.

Jones Mwakabuku, a Tanzanian gem dealer is studying the transparency of a Winza ruby rough in Arusha gem market.

April 16, 2008: After our short visit to the Arusha gem market, we took the road to Dodoma. Our second step in this expedition to Winza was to meet the Dodoma Regional Mining Officer in order to get his support to visit the Winza mining area. The fact is that in Tanzania foreigners are not allowed to visit gem mining areas without permission.
On the way to Dodoma we could enjoy the African country side: It was beautiful and very green as the rainy season was just passed. We got very lucky on our expedition as few weeks before it would have taken us much more time to go and to return from Winza as the roads were then very muddy.

April 17, 2008: We met Mr. Komu, the acting resident mining officer at his office, near the Geologic Survey of Tanzania. We had a long interesting discussion about gemstone mining in Dodoma province and we could also study some additional stones coming from Winza. Mr. Komu agreed to issue an introduction letter for the local authorities at Winza and to provide us the support of Mr. Innocent, a mining technician from his Dodoma office, in order help us during our visit to the Winza mining area.

Mpwapwa: From Dodoma we drove to Mpwapwa, the local gem trading center for Winza mining area. As I wrote before, foreigners are not allowed to work in mining areas. The gem buyers (mainly from Thailand and Sri Lanka) have then decided to settle in Mpwapwa in order to buy gems from the Tanzanian brokers traveling back and forth from the mines. M Innocent, the mining technician from the Dodoma mining office traveling with us told us that 12 registered buyers were present at Mpwapwa. Among them 11 were Thais and one Sri Lankan. He told us that about 40 non registered buyers were also present in town (20 Thais, 10 Sri Lankan and 5 Indian).
It was interesting to see many signals advertising for different buying companies were visible in Mpwapwa indicating that a fierce competition was already taking place between the different buyers in order to buy the stones from the Tanzanian gem brokers.
We could see also that the foreign gem buyers were also buying, painting and building houses in Mpwapwa which started to have an atmosphere similar to what we saw commonly in Ilakaka or Tunduru. The arrival of thousands of gem miners and of hundreds of foreign gem buyers in Mpwapwa region is obviously a major change for the area. It brings probably good and bad as reported by Anglican missionaries.

Buying fine quality gems in Mpwapwa is not an easy job as reported by Mr. Mor, a famous Thai gem buyer from Chanthaburi, working in Mpwapwa at the time of our visit and other foreign gem dealers: Synthetics are very common in the area and even experienced gem buyers lost large amount of money buying synthetics instead of natural gems.

On the following photo, Mr. Mor presents us a parcel of natural Winza rubies on the left and two synthetics, of the type commonly found at Winza, on the right. In order to separate natural Winza gems from common synthetics he told us that he was using a simple color filter. But if the color filter can separate iron rich Winza rubies from iron poor flame fusion synthetics, it is not useful with some iron containing synthetics like some Ramaura or Kashan flux grown rubies.

Reporting about our presence to the local Mpwapwa police station, we had an interesting discussion with the Mpwapwa police chief who allow us to study an old map of the Mpwapwa district decorating his office. This map from the British colonial times (1950's) was very interesting to us as we could see some mining symbols near the location of the current gem mining in the south of the Winza village. As we can see on the map the mining takes place on both side of a river on the west of the "Mangalisa Forest Reserve" in an area which was reported by locals to have been work at small scale for copper, mica and garnets in the past by Greek miner Georges Paparas and other people.

On the way to Winza, we could appreciate the scenic beauty of the area with on the left side the majestic shape of the Yalumba mountain..
Arriving at Winza: This small village is composed of few houses surrounded by corn fields. Corn farming was reported to be the main resource from Winza people. People in Mpwapwa told us that a corn farmer from Winza village was probably mining for many years the area in secret. The farmer activities were kept secret for years until he passed away recently. Then his son, Mr.Shabani, got the secret of the location of the mine few days before the death of his father. He started to mine there and went regularly to Dar es Salaam to sell his gems to Thais and Sri Lankan gem dealers. He was soon followed by people and in November and December 2007 people in the Tanzanian gem trade started to know about rubies from the area and started to travel to Winza to mine and trade rubies.

What does Winza village looks like? Here is a short drive video I did passing through the quiet Winza village: A school, few houses scattered here and there. Most of them are surrounded by corn fields...

Just Lovely!

Video: Vincent Pardieu.

Another view of Winza village: A peaceful farmer community living around its school.
Driving on the way to Winza we could encounter several local bus transporting miners and supply for the 4000 to 5000 people living and working at the mining area. All the buses and trucks we passed were fully loaded of people food, water and mining tools.
Approaching Winza, we drove through several muddy areas as few short rainfalls were still common. Nevertheless it was not a serious challenge for our car and driver, but few weeks before we would have possibly need one full day to travel from Mpwapwa to the mining area. On April 17, 2008 it took us just four hours to reach the mines from Mpwapwa town.

6) Arriving at the "Winza mines"..

The area and the mining camp are locally known as "Mtakanini area" meaning "what do you want?" in Swahili language. It is located on the river banks of the locally known Winza river (in fact the "Mtindiri River as we can see on Whittingham map, 1953) just down the Mang'alisa mountains.

Here is a short video taken near the Mtindiri River while we were approaching the Mtakanini mining area near Winza: These were our very first moments watching the ruby mining activity at Winza ...

Video: Vincent Pardieu.

A closer view on the gem washing area on the Mtindiri River banks just near the Mtakanini mining camp: About 100 gem miners were there washing the gem rich ground collected from the area nearby.
On April 17th in the late afternoon to enter Mtakanini mining village we had first to pass the Mtindiri River, our first vision of Winza mining was then of course the washing of the gem rich ground near the Mtindiri River. We returned to the washing areas later on April 18 and 19. We could then discover that there were three areas where washing was taking place. I invite you to witness the washing activities at Winza with the following photos:
Typically, the gem rich ground collected in the mining area is taken to the river using trucks, bicycles or simply carried by men. The gem rich ground is then stocked before to be washed.
During our visit at the end of the wet season, enough water was available at the Mtindiri River for the washing activities but the level of the river was obviously already low. As the dry season advanced during summer 2008, the water supply became a major problem for the miners. At the end of June 2008, I was informed by Abdul Msellem that miners were building dams and ponds in the Mtindiri river bed in order to store enough water to continue washing the gem rich ground, but obviously as in all mining areas, water supply is a major problem during the dry season.

Here is a short video showing the Winza ruby and sapphire washing area near Mtakanini camp: Gem miners are washing here the gem rich ground collected in the hills in order to collect rubies.

Video: Vincent Pardieu.

On the following photos, I invite you to discover the result of the washing at the Mtindiri River: Rubies, pink, purple, blue sapphires very similar to the stones we saw in Arusha and Mpwapwa gem markets. Nothing really surprising but a nice confirmation...
After visiting the washing area, we followed the miners to the main mining camp located few hundred meters from the washing areas.
Mtakanini mining camp:
A closer view on the Mtakanini mining camp from the Mtindiri River behind the corn fields. If at the end of January 2008, Abdul Msellem in his first report told me that about 600 people were living there, at the time of our visit in April 2008 we were reported that about 3000 to 4000 people were working and living in wood, plastic and aluminum huts at Mtakanini. Malaria was present in the area and people were sleeping under mosquito nets. Beginning July we were reported that the number of miners had increased since our visit and about 6000 people were possibly living and working there despite the fact that the water was becoming rare at the Winza river.
On the following photos you can discover the atmosphere in the centre of Mtakanini mining camp: it is arranged around a large central area where the trucks and the buses are bringing people and supply.

Here is a short video taken while we were first entering the Mtakanini mining village near Winza on April 17th 2008. It was night fall and the miners mistook me first for "Malapa" alias Werner Spaltenstein a very famous Swiss buyer in East Africa.

Video: Vincent Pardieu.

If during day time life when all the miners as busy at the mines or at the washing area, the area looks peaceful and very quiet, after night fall the Mtakanini central area with its small hut restaurants and bars becomes crowded and noisy as hundreds of miners gather there to celebrate their luck or discuss business as we could witness during the 2 nights we spent in this mining village.

Here is a short video showing Winza Mtakanini mining camp at night: If by day Winza mining camp is quite quiet, as most miners are working at the mines or at the washing area, by night the camp is crowded with people eating, speaking business, celebrating their luck or trying to forget their problems.

Video: Vincent Pardieu.

After arriving at the new ruby mining area in Winza, Tanzania, we joined the miners for diner in the center of the mining camp: Food was simple but with 5000 miners around that first night at the mines turned to be far away from boring for the two visiting "Musungu" and I'm sure that our police escort will remember it also...

Video: Vincent Pardieu.

A closer view on a classic Winza miner hut:
The Mtakanini mining area is not yet old enough for people to start building permanent housing. Miners and traders are then living in these simple wood and plastic huts. The fact is that if many miners have applied for mining licenses Mr. Innocent, the mining technician from Dodoma told us that they were still not confirmed and the process could take several more months. For miners it means that depending of the government decision they will be able to continue to mine here or not. This situation means that miners at Winza are so far more concerned about short term profitability than anything else.
If we could meet at Mtakanini many friendly miners we met in the 2005 or 2007 in other Tanzanian mining areas (Tunduru, Songea, Mahenge, Merelani) some miners were obviously not welcoming our arrival at Mtakanini. For security purpose we had to stay each night at the local police tent and we could see during our first night that the 4 men strong police force was very busy to keep the 5000 people Mtakanini camp peaceful. We understood the following day that if people understood that we were not gem buyers trying to by pass the local dealers making a living from buying gems from the miners at Mtakanini and traveling to sell them in Mpwapwa, some miners were suspecting that we could be geologists send by a powerful foreign mining company in order to make a survey which would possibly result in this company taking over the Winza mining area. Merelani miners who experienced such take over at the Tanzanite mines were among the most active in order to find a way not to allow us to visit and study the area. This situation was interesting as we could then understand the way things were organized at Mtakanini: To summarize there were the village authorities with a chairman, his vice chairmen and a secretary trying to organize the life at the mining camp and there was also a similar structure for the miners.
We spent then the morning and a part the afternoon of April 18 to explain to the local authorities the reasons of our visit. We had then the "subili kidogo" attitude, meaning "wait a little bit" in Swahili as we spent hours waiting for the miners and the villagers to discuss and finally agree on the fact that we could visit freely the area. Finaly 24 hours after our arrival at Mtakanini, Mr. Hamad O.Msuya, the chairman of the miners, who just returned to the mining area released us from our "Subili Kidogo" period: Within few minutes, after a rapid talk with Mr. Innocent, the Dodoma mining technician and after checking the introduction letter from the Dodoma mining officer he allowed us to visit the mine and do our work. To help us he asked one of his vice chairmen: Mr.Kinana Kirenga, an old Massi gem dealer, to take us around. He also asked to the police chief to provide us an armed escort.
We were then free to visit the mining area and take photos.
I would like to use this occasion to thanks all the Winza people who welcomed us and helped us during our stay at Mtakanini. I wish them good luck and hope that they will appreciate this expedition report.
Around the Mtakanini central square, several gem brokers are waiting in front of their hut for the miners returning from the mines or from the washing area using a very simple table on which sometimes we could find some nails placed here to avoid people to seat of the working table...
Most of the rough buyers in Winza use only two simple tools to buy gems: A powerful torch light in order to find out if the rough ruby is clean or if it is full of fractures and inclusions and then some pliers to take out the gems from their matrix or to eliminate from the rough some area which could lower the beauty of a gem parcel.
The author studying some rough Winza ruby from a large parcel. During our visit we saw frequently parcels weighting several kilos. Nevertheless only few stones in these parcels were really gem quality as it is the case in most primary mining areas. Most of the stone we saw were without great surprise cabochon grade to the best.

Mr. Kinana Kirenga, the Mtakanini miner Vice Chairman who came with us to visit the mining area is presenting us a parcel of good quality but small pinkish Winza rubies.


Most of the stones found at Winza were found after washing the ground collected over the Mtakanini camp. Most of the rough stones are then free of any matrix. High value very fine color and and exceptionally clean pieces of large size were found. These stones are nevertheless rare.

Waiting at the police station to get the approval of the miners and villagers to visit the mining areas and later visiting the gem buyers waiting for the miners to come to seel them their stones, we could see many people walking through the Mtakanini village carrying on their back bags full of gem rich ground.

As soon as we were granted the authorisation to visit the mining area we decided to walk to the area were these bags were coming from...

Few hundred meters after the entrance of the village on the hill side we arrived to an area where we could see several tens of miners digging the ground filling back and loading trucks.
Here was then the place where the beautiful stones we saw at the lab earlier that month were probably coming from. We collected first the GPS data of our location for our data:
(07° 05'03"S and 36°19'11"E) and studied the area around. It was an incredible scenery. The area was locally looking like a first world war battle field, Verdun style...

Here is a short video showing a global view over the ruby and sapphire mining area on the hill near the Mtakanini mining camp near Winza village, Tanzania.

Video: Vincent Pardieu.

As usual when 6000 people arrive in a wild area to find gems from the ground, the local environmental impact is of course not insignificant: As the ground is collected, the trees fall down and are let to dry on site. Their wood will be probably used later for housing or cooking. It seems destructive but nevertheless I would like to invite the reader to understand that such gem mining activities only affect here a small area (about 500m by 500m which means about 25 ha in the case of what we could see at Winza). The damages created to the forest are then very small compared to the potential impact of timber business or compared to consequence of the common bush fires which destroy each year during the dry season hundred of thousands of hectares of forests in East Africa as we could witness during our previous visits in Tanzania in 2005 and 2007.
We continued then our visit meeting the miners in order to get a closer look to their mining operations:

Approaching the mines on the Mtakanini hill we could see that if many miners were just collecting ground to wash it at the river, several groups had started to mine some ruby and sapphire rich solid rocks located under the gem rich ground.
After such observations it can be concluded that the deposit is a mixed "elluvial" and "solid rock" type deposit.
We could visit several operations which were told us to be less than one month old. These hard rock mines were to the best 10 meters deep.

Here is a short video showing a starting underground ruby mining operation at the Winza mining area in Tanzania. After the ruby discovery in the ground, gem rich hard rock veins were found and the Tanzanian miners used to the deep tunnels of Merelani were not long before to start digging.

Video: Vincent Pardieu.

Here is a second short video showing the same starting underground mining operation. Just a closer look to the way the miners are working with simple hand tools... As fuel prices are rising, this type of gem mining will probably have a bright future.

Video: Vincent Pardieu.

Most of the miners starting these hard rock operations told us that they were working in the past at Merelani where the underground tunnels can be 300 to 400 meters deep underground. We had no doubts then that after few more months the tunnels would be probably much deeper especially if fine stones were found in hard rock.

Approaching the mines on the Mtakanini hill So far miners explained us that they were following gem rich veins composed mainly of a dark black rock as we can see on the right of the photo on the left.
The veins are nearly vertical. Near these dark rocks (which were identified as amphibolites) we could see numerous large mica sheets and a whitish very soft rock (possibly talc or kaolin) which nature is still not clear.

On the following photos you can now discover the gems found in these hard rock mines. The stones are usually more pinkish to purplish than red and most of them also present some blue areas. So far I was not able to see any truly red stones from these hard rock mines and after investigation at the lab it seems that the typical inclusion scene of these stones is quite different from what was commonly found in the top quality stones from Winza which were reported to have been found in the ground over these gem rich hard rock veins. Advanced chemical and spectral studies of these different gems nevertheless confirm that these stones are probably coming from the same area but possibly from a different vein. The main question is now to find out if the vein producing the top quality stone is still to find or if, to the contrary, it does not exist anymore due to natural erosion...
The following specimen presented to us by gem miner Emmanuel Joeli Sikawa is interesting as it is a large specimen associated with amphibole and orange garnet. Most of the crystal was taken out from the matrix and remains on the amphibole we can see a large area mainly blue and a more pinkish one.

Mr. Emmanuel Joeli Sikawa spent a lot of time with us on April 18 and 19 2008 at the mines. His presence and explainations were very useful for us to understand the mining at Winza.

His personal professional background is interesting to understand the reality of gem mining in Tanzania: Emmanuel was 28 years old in 2008. He started his professional gem mining life when he was around 15. He worked then for 10 years at Merelani. Then he worked for one year at Ipanko spinel mines near Mahengue before to return to Merelani for another year until he heard about Winza in January 2008.
He moved then to Winza where he was financing several mining pits and about 30 to 40 miners were then working for him.



Details on the specimen collected from Emmanuel Joeli Sikawa on April 19th 2008 at Mtakanini hill. This specimen is currently part of the Gubelin Gem Lab reference collection. We can clearly see the small orange garnet crystals and the amphibole matrix.
The same specimen associated with rubies and sapphires collected from the ground which was washed at the Winza river. We can see that the material is heavily zoned with blue area and that some specimens have an interesting crystal shape reminding spinel crystals.
Another parcel of Winza rubies in which the stones does not look this time to present many blue zoning areas. If blue color zoning is present in Winza rubies we nevertheless saw many crystals without any blue zoning.
To complete this study here a detailed photo of the two exceptional faceted rubies presented on the lead photo of this page. The stones are over 5 cats for the smaller one and over 10 carats for the larger one. During 2008 Winza, and Tanzania produced obviously some truly exceptional gems!
Stones courtesy: Van Cleef and Arpels / Piat / Swala Gem Traders, Photo: V.Pardieu / Gubelin Gem Lab, 2008

Another interesting specimen coming from the Winza deposit: Its shape is locally called in Tanzania "spinel shape" as it reminds the appearance of spinel crystals found in Mahenge and Matombo areas of the Morogoro province. I prefer to say "pseudo octahedral" as proposed in the G&G Winter 2008 Winza article p330.
Besides the ruby part, which was found to have a similar chemistry with the other Winza rubies we collected , we can notice some kyanite (disthene) and a tiny amphibole crystal.... Very unusual and also interesting as the presence of disthene suggest that the Winza deposit is related to metamorphism.
I did not collect this sample during my expedition in Winza in April 2008, I purchased it in Sainte Marie aux Mines gem and mineral show on June 28th 2008, in Alsace, France: It was part of a large parcel collected by German gem dealer Werner Radl who visited the Winza mining area in May 2008 few days after me.
The sample got my attention as it is quite similar to another sample presented to me on May 05th 2008 at the Société Suisse de Gemmologie (SSG) yearly meeting at Flüeli-Ranft in Switzerland by Prof Hanni from the SSEF. Prof Hanni told me that he got his sample in Bangkok, Thailand from Swiss Gem trader Werner Spaltenstein, who travels regularly to Tanzania to buy gems.Prof. Hanni was very interested by this kyanite and ruby association, so was I. I provided this sample to geologist Gaston Giuliani of the CRPG, Nancy University (France) for further investigation.
The crystallography of Winza rubies and sapphire is quite unique and very interesting. A good study about these aspect was printed in "Rubies and Sapphires from Winza, Central Tanzania"by Schwarz&al in Gems & Gemology, Winter 2008 edition. I invite those interested by more details about this fascinating aspect to study that article.

On the following photo we can see some details of the surface of this unusual sample.
Here are several inclusion photos from Winza rubies

Brief summary of the gemological properties of rubies and sapphires from Winza, Tanzania
(For more details please see "Rubies and Sapphires from Winza, Central Tanzania"by Schwarz&al Gems & Gemology, Winter 2008, Vol. 44, No. 4, pp. 332)

Color: Red, purplish red, pinkish red, orangy red, blue, pink, padparadsha.
Refractive Index: No: 1.767-1.771 Ne: 1.758-1.762
Birefringence: 0.008 - 0.010
Specific Gravity: 4.00 - 4.03 (average 4.02)
Dichroism (ruby): Orange to orangy red and purple red to violet red
Origin of Color: Cr, Fe
SWUV: inert to weak
LWUV: Weak to strong
Chemical Fingerprint: Commonly High Fe and Cr (about 0.5%) and low Ti, V, Ga (often below detection limit of EDXRF)
FTIR: (In unheated stones: Commonly peak at 3160nm and/or broad band at 3450nm)
UV-VIS: Cr modified usually by Fe,
Crystal Morphology: Rhombohedron (positive and negative), prismatic (short and long), dipyramidal and tabular (rarely).
Inclusions: Typically: Long, curved, tube-, fiber-, needle- or hair like inclusions (only in rubies), crystals (greenish amphibole, orange garnet, apatite were so far identified using Raman by the author and Dr. Eric Erel of the Gubelin Gem Lab.) partially healed fissures with polyphase fillings or solid material of unknown nature (not active in Raman), blue color zoning, rhombohedral twin planes and sometimes intersection tubes in several directions, minute exsolved particles.


1) Inclusions found so far only in top quality red Winza material:

(All photos: V.Pardieu/Gubelin Gem Lab, 2008)

Long tube-, needle-, fiber-, or hair like inclusions are the most characteristic inclusion found in many fine Winza rubies. These inclusions were so far not observed by the author in any Winza sapphires.

Previous and next photos: Here the curved tube like inclusions are associated with bands of minute particles (40x).

Previous and next photo: Again the same curved tube like inclusions now associated with strong growth lines (40x)

Previous photo: In some rare cases, some amphibole crystals (identified using Raman by Dr. Eric Erel) can be found associated with curved tube like inclusions in fine quality Winza rubies (40x)

Previous and next photos: Commonly encountered in fine quality rubies from Winza are some irregularly shaped cavities filled with a greyish substance which are not without reminding flux type inclusions in synthetic rubies (40x)

Previous photo: One of these irregularly shaped cavities seen using dark field illumination.(40x)

Previous photo: The same irregularly shaped cavities seen using bright field illumination.(40x)

Previous photo: Again the same irregularly shaped cavities seen using cross polars illumination.The polycrystaline nature of the inclusions is now obvious.(40x)

Previous photo: Datails on the paralel growth zoning in one fine Winza ruby. Commonly bluish violet lamelae can be seen using dark field illumination.(40x)

2) Inclusions found "polychrome" type Winza rubies and sapphires:

(All photos: V.Pardieu/Gubelin Gem Lab, 2008)

Previous and following photos: One of the most common inclusion scene in Winza sapphires is color zoning. If some stones are pink and other blue, most of the Winza sapphires are in fact bicolor.

Previous and next photos: Besides blue color zoning, clouds or bands of minute particles are also commonly found in Winza rubies and sapphires. They can give to the stone a milky aspect.

Previous and next photos: Another common inclusion found in most Winza sapphires, in assciation with color zoning and clouds, are healed fissures.

Previous and next photo: Details on healed fissures in Winza sapphire: These healed fissures can be look to the fisrt glance like in many healed fissures found in sapphires from other origins.(dark field illumination, 40x)

Previous and following photos: Nevertheless a close observation of these healed fissures under bright field illumination often reveal that they contain multiphase fillings as it can be seen in the previous photo (bright field illumination, 60x) and the following one (cross polars illumination, 60x)

Previous and following photos: Another couple of photos from bright field to cross polars illumination showing multiphase fillings of unknown nature (not active in Raman) in healed fissures. . Previous photo: bright field illumination, 40x and the following one: cross polars illumination, 40x

Previous and next photos: Rhombohedral twinning is also commonly found in Winza sapphires.(10 and 40x)

Previous and following photos: Intersections of the twin lamellae often result in the formation of linear tubules, usually one system but also commonly three dimentional networks as here. (30x)

Previous photo: A rather rare inclusion scene in Winza sapphires are stringer like formations composed of coarse particles.(40x)

Previous and following photos: Surface reaching fissures and tubes are commonly filled with limonite like orangy substance (40x)

Previous and following photos: One very common inclusion in Winza rubies are greenish euhedral amphibole crystals which were identified using Raman by the author and Dr. Eric Erel. (30 to 40x)

Previous photo: With bright field illumination we can see several amphibole crystals (40x)
Next photo: With fiber optics illumination we can see many orientated particles, probably hematite platelets. (40x)

Previous and following photos: Again we can see on the previous photo a fine association of greenish amphibole and orange garnet inclusions using fiber optics illumination we can also discover a dense network of reflective particles, probably hematite platelets. (20 to 40x)

Previous and next photos: Garnet inclusions in Winza sapphires are usually rounded and orange in color. On the previous photo, the black looking crystals are in fact cavities filled with polishing powder as the inlcusions are here reaching the sample surface. (30 and 10x)

And finally a rare inclusion in Winza sapphires: An apatite crystal which was identified by Dr. E. Erel using Raman.(40x, Dark field Illumination)

Very Special Thanks,

To all the Tanzanian authorities we met for their support and help, and particularly Mr.Komu, acting resident mining officer in Dodoma to have permited us to visit Mpwapwa and Winza and provided us all the documents we were needing during our visit and to have asked Mr. Innocent, mining technician in Dodoma, to escort us in order to facilitate our expedition. .

To all the miners, gem brokers and policemens who welcomed us, shared with us their time and their life and particularly: Mr. Hamad O.Msuya, Mr. Emmanuel Joeli Sikawa and Mr. Kinana Kirenga whose support was priceless and particularly appreciated.

I hope that this report will be useful to all people we met in Tanzania and to all the people interested in the gem trade from the production areas in Tanzania to the consuming markets and for all gem lovers around the world.

Now I would like to give a more personal thanks to the following people as without their help and support during this expedition to Winza Tanzania, I would not have succeeded in this expedition:

First thanks to my traveling companions who helped to finance, organize and to make this expedition a success:

Jean Baptiste Senoble is a young French gemologist working currently as gem dealer with Nomad's in Bangkok, Thailand. His love for gemstones and gem people is second to none. He was my student at AIGS in Bangkok in 2004 and my traveling companion during the four months long expeditions to South East Asia and Africa in 2005. This new expedition to Tanzania was a good occasion for us to discover a new aspect of the Africa we felt in love with in 2005.
Abdul Y.Msellem was our guide during all our gemological expeditions to Tanzanian in 2005, 2007 and 2008. He was recommended to us by Eric and Mark Saul in 2005. Abdul is a professional gem broker and an occasional gem miner in Tanzania. His father was already in the gems trade and Abdul knowledge about Tanzanian gem mining areas and gem trade is just incredible. People willing to contact him can join him at the following email:

We would like to present him here all our gratitude for all his help before, during and after our expedition.
Thanks to Abdul support, attitude and dedication our expeditions turned to be very successful. Really thanks!
Moussa, our driver, is a safari driver for "Fortes Safari" company in Arusha. His professionalism, great experience about driving in the bush and positive and enthousiastic attitude during all our expedition were greatly appreciated. I highly recommend Moussa for any possible expedition in Tanzania.

Then to the ICA (International Colored stone Association) and its Tanzanian members
for the support they provided to the fellow member I'm to organize this expedition to Tanzania.

Eric and Mark Saul, from Swalagemtraders and their father: geologist John Saul which name is associated with the ruby discoveries in Kenya.
Eric Saul is the current ICA Ambassador to Tanzania. Mark, who also visited Winza during summer 2008, was able to collect some key geological samples which were really helpful for the G&G article where his father John Saul was a co-author. Their support in the planning, the organization and the aftermath of our expedition was very valuable and much appreciated.

I would like also to thanks:

The people who helped me while working on Winza gems giving me access to some interesting samples for study or photography like Aline De Lavoreille from Van Cleef and Arpels and Emmanuel Piat from Piat.

The people who provided me some useful reports and information like Werner Radl, from Germany, Mr Mor and his daughter Wilarwan from A&W Gems in Chanthaburi, Thailand.

I would like also not to forget:

Geologist John Saul, is a world wide well known expert on East African gem deposits. He discovered the famous "John Saul Ruby Mine" in Kenya during the 1970's: It was a real pleasure to meet him in Arusha before and after our expedition to Winza and to work later with him on the Winza article for Gems and Gemology. His correspondance was very useful for me to build this page.
Swiss gemologist Walter Balmer for his friendship and in this particular case to have provided me some useful old geological publications and map about the Winza area and to have helped me on different issues regarding this page..
Walter is one of my regular traveling companions. He is also (like me...) a former gemologist from the Gubelin Gem Lab, in Lucerne, Switzerland and is currently finishing a PHD on the geology of ruby deposits in Tanzania and Madagascar at Chulalongkorn University in Bangkok, Thailand where I also currently live.

Finally I dont want to forget the people I collaborate with while working as a lab gemologist on gems from Winza:

Very special thanks also to Schwarz D., Saul J.M., Schmetzer K., Laurs B.M., Giuliani G., Klemm L., Malsy A.-K, Erel E., Hauzenberger C., Du Toit G., Fallick A.E., Ohnenstetter D. for their great attitude and appreciated collaboration working on "Rubies and Sapphires from Winza, Central Tanzania." an article published in Gems & Gemology, Vol. 44, No. 4, Winter 2008, pp. 322-347

Last but not least: Very special thanks to the Gubelin Gem Lab in Luzern, Switzerland, my fellow gemologists and former colleagues working there for their great and appreciated support for the Winza April 2008 expedition. A very special thanks to Suzie Gubelin to have taken the time to share her personal feelings about the beauty of Winza rubies and sapphires. It was most educative to me.

Interesting Links and recommended readings about gemstones from Winza:

- Feb 05, 2008: Frist announcement about the new ruby and sapphire discovery near Dodoma by the author on the GemologyOnline gemological forum
- May 03rd 2008, first serious public release about rubies from Winza: SSEFnewsletter_may08
- May 05th 2008, GIA Insider published an article about Winza by SSEF
- May 06th, 2008, The Gubelin Gem Lab makes a public announcement about rubies from Winza in its newsletter:
- May 26th 2008, GIA Insider published a short article by Brendan Laurs and Vincent Pardieu about Winza
- June 03rd 2008, the ICA put online its InColor Magazine: with an article from JB Senoble about our common expedition to Winza and another gemological article by SSEF about these Winza rubies.
- June 05th 2008: GIT put on its website a short study about Winza rubies:
- July 04th 2008, Diamond Rapaport Report, Vol 31, N26, p173 to 175: "Field Report from Winza" by Vincent Pardieu and Dietmar Schwarz, Gubelin Gem Lab. Note: In this article the deposit was mistakenly described as "probably lamprophiric..." It is of course not the case.
- Jan. 2009: Schwarz D., Pardieu V., Saul J.M., Schmetzer K., Laurs B.M., Giuliani G., Klemm L., Malsy A.-K, Erel E., Hauzenberger C., Du Toit G., Fallick A.E., Ohnenstetter D. (2008) "Rubies and Sapphires from Winza, Central Tanzania", Gems & Gemology, Vol. 44, No. 4, pp. 322-347.

Interesting Links, articles, maps and books about gemstones from Tanzania: (to be completed)

- Vincent Pardieu and Jean Baptiste Senoble 2005 expedition report to Tanzania
- Vincent Pardieu, Richard W Hughes, Guillaume Soubiraa, Mike Rogers, Warne and Monty Chitty and Philippe Brunot 's October 2007 expedition report to Tanzania
- "Tanzanite: Its discovery and early days" by John Saul - ICA's InColor Magazine . Summer 2007
- "A new spessartite discovery by the Serengeti" by Eric Saul from Swalagemtraders...
- "Color change garnets" by Swalagemtraders
- "The first gemstone discovered in East Africa": (The discovery of ruby near Longido) by John Saul.
- "Tanzanite July 7, 1967, something new out of Africa", by Swalagemtraders
- "Tsavorite, history of the main deposit" by Swalagemtraders
- Gems and gemology, spring 2004, Featured Gem News: "Pink to Pink-Orange Spinel from Tanzania"
- "The mineral industry of Tanzania 2003"
- "Tanzanian spinel, racing for the red", by David Federman
- "Longido ruby" As described by Edward R. Swoboda by
- "Tanzanite buying guide" by Peter Bancroft by
- "Tsavorite Garnet, King of African Gems" by Richard Wise
- "Green future await Tanzanian gem miner" by: Gerrit Bezuidenhout
- "Tanzanian Ruby Find Brings Hope" by Hamza Kondo
- "Rukwa, Tanzania Unknown Gem giant" by Hamza Kondo
- "The SEAMIC in Tanzania" One of the few facilities in Tanzania offering gemological courses.
- "TanzaniteOne", the website of what is probably the world colored stone most high tech mine.
- "Research on Corundum and chrysoberyl from Tanzania completed" by SSEF

Recommended Articles about gem localities in Tanzania:
- "The geology of the Nyanzwa area", by J.K. Whittingham, Quarter Degree Sheet 63 NM.
- "Alexandrite from Lake Manyara, Tanzania", by E.Gubelin, Gems & Gemology, Fall 1976
- "Garnets from Umba valley, Tanzania: Is there a necessity for a new variety name?" by K.Schmetzer, Journal of Gemmology, 1981, XVII, 8
- "An Unusual garnet from Umba valley, Tanzania" by K. Schmetzer, Journal of Gemmology, 1982, XVIII, 3
- "Reddish-brown sapphires from Umba valley, Tanzania" by M. Gunawardene, Journal of Gemmology, 1984, XIX, 2
- "Korunde aus dem Umba-Tal, Tansania, by H.A. Hanni, Z. Dt. Gemmol. Ges., Oct 1986
- "On corundums from Umba Valley, Tanzania" by H.A. Hanni, Journal of Gemmology, 1987, 20,5
- "Well-formed tsavorite gem crystals from Tanzania" by R.E. Kane, A.R. Kampf, H.Krupp, Gems & Gemology 1990
- "Tectonic Settings of Gemstone Mineralization in the Proterozoic Metamorphic Terrane of the Mozambique Belt in Tanzania", by E.Malisa and S.Muhongo (1990) Precambian Res., 46:167-176
- "New rubies from the Morogoro area, Tanzania" by H.A. Hanni and K.Schmetzer, Gems & Gemology, Fall 1991
- "Gem quality green Zoisite" by N.R.Barot and E.W. Boehm, Gems & Gemology, Spring 1992
- "Gem Wealth of Tanzania" by D. Dirlam, E B. Misiorowski, R Tozer, K.B. Stark and A.M. Bassett, Gems & Gemology, Summer 1992
- "Lamellar inlcusions in spinels from Morogoro area, Tanzania" by K.Schmetzer and A. Berger, Journal of Gemmology, 1992, 23,2
- "An examination of colour change sapphire from Tanzania", by R.C. Kammerling, M.L.Johnson, Y.Liu, The Australian Gemmologist, Second Quarter 1996
- "A new colour change effect" by A.Halvorsen and B.B. Jensen, Journal of Gemmology, 1997, 25, 5, 325-330
- "Sapphire and garnet from Kalalani, Tanga province, Tanzania", by A. Siefert and J. Hyrsl, Gems & Gemology, Summer 1999
- "Chemical fingerprinting of some East African gem rubies by Laser Ablation ICP-MS" by A.H. Rankin, J.Greenwood, and D. Hardgreaves, Journal of Gemmology, 2003, 28,8,473-482
- "The ICA 2006 World Colored Gemstone Mining Report", InColor Spring 2006.
- "My road to the discovery of Tsavorite" by C. Bridges, from "Into East Africa, a Journey to the Source", InColor 2007
- "Tanzanite: Its discovery and early days" by J. Saul, from "Into East Africa, a Journey to the Source", InColor 2007

"Gems News" and other "Gem News International" from Gems & Gemology : (To be completed...)
- "Tanzanian spinel", Gems & Gemology, Fall 1991, p183 (about Mahenge spinels)
- "Update from Tanzania", Gems & Gemology, Fall 1991, p183 (about Longido ruby)
- "Large Tsavorite garnet from Tanzania", Gems & Gemology, Winter 1991, p258-259
- "Update on Tanzanian mining", Gems & Gemology, Winter 1991, p262 (about Tanzanite at Merelani)
- "Faceted ruby from Longido", Gems & Gemology, Fall 1992, p203
- "Ruby mining near Mahenge, Tanzania", Gems & Gemology, Summer 1993, p136
- "Sapphires from Tanzania" Gems & Gemology, Spring 1995, p64-66
- "Sapphires and other gems from Tanzania", Gems & Gemology, Summer1995, p133-134
- "Update on Tanzanite mining", Gems & Gemology, Summer 1996, p135 (about Tanzanite at Merelani)
- "A new source for Tsavorite", Gems & Gemology, Summer 1999, p151-152 (about Ruangwa)
- "Ruby from Songea, Tanzania", Gems & Gemology, Winter 1999, p215
- "Another source of bicolor sapphire, Tunduru, Tanzania", Gems & Gemology, Winter 1999, p215
- "Update on Tanzanite mining by AFGEM", Gems & Gemology, Winter 2003, p337-339
- "Large tsavorite and green grossular from Tanzania", Gems & Gemology, Spring 2004, p72-73
- "Pink to pink orange spinels from Tanzania", Gems & Gemology, Spring 2004, p71-72
- "Control on Mineralization in Bloc D' of the Merelani Tazanite Deposit, Tanzania", Gems & Gemology, Fall 2006
- "Geology and Mining of Southern Tanzanian Alluvial Gem Deposits", Gems & Gemology, Fall 2006, p107
- "Transparent dumortierite and sapphirine from Tanzania", Gems & Gemology, Winter 2007, p379

- "Central Tanzanian tectonic map: A step forward to decipher Proterozoic structural events in the East African Orogen". Authors: H. Fritz, V. Tenczer, C.A. Hauzenberger, E. Wallbrecher, G. Hoinkes, S. Muhongo, A. Mogessie. Source: Tectonics, 24, TC6013, pp. 26. Published Year: 2005
- "Geology and Gemstones Deposits of East Africa", Y. Deschamps, et al. (2004), BRGM
- Regional geological map: by J.K. Whittingham, Scale of 1:125’000, Quarter Degree Sheet 198, Geological Survey of Tanganyika, 1954.

Recommended Books:

"Gemstones from East Africa" by Peter C. Keller (1992)
"Ruby and Sapphire" by Richard W. Hughes (1997)
"Rubin, Saphir, Korund" extraLapis No. 15 (1998)
"Corindon et Spinelles" by F. Cresbron, P. Lebrun, J.M. Le Cleac'h, F. Notari, C. Grosbon, J. Deville, Mineraux et Fossiles, Hors Serie No.15, Oct 2002
"Saphirs et Rubis, Les gisements de Corindon: Classification et Genese" by V. Garnier, G. Giuliani, D. Ohnenstetter, D. Schwarz, Le Regne Mineral No.55, Jan. 2004
"Geology of Gem Deposits" by Lee A. Groat, Mineralogical Association of Canada, 2007


The Author at Winza, April 2008. Photo by Jean Baptiste Senoble

Hoping that you have appreciated this visit to Winza and inside Winza gems.

All the best,

Vincent Pardieu, Feb. 2009

(This page was last edited on Feb 12, 2009)


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Important Note: Vincent Pardieu is an employee of GIA (Gemological Institute of America) Laboratory Bangkok since Dec 2008. Any views expressed on this website - and in particular any views expressed by Vincent Pardieu - are the authors' opinions and do not necessarily reflect the opinions of GIA or GIA Laboratory Bangkok. GIA takes no responsibility and assumes no liability for any content on this website nor is GIA liable for any mistakes or omissions you may encounter. GIA is in particular not screening, editing or monitoring the content on this website and has no possibility to remove, screen or edit any content.