Thanks and disclaimer:


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.


Website Map


Index page: Vincent Pardieu's Blog

About the Author

About me : How did a countryside Frenchman became a "Shameless travel addicted gemologist"? ( Under construction)


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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)

Find our blogs using the following Keywords:

Find our photos using the following Keywords:

Discover fieldgemology newsletter:
(Currently under "hibernation status"...)

Number 01: Sept 2006
(I know: it was long time ago...)



THANKS for their support
for our field expeditions since 2005:


about gems, gemology, field expeditions, studying gemology, minerals, jade, pearls or jewelry?
We recommend these FORUMS
where the author is contributing:

Do you want to

Here are some recommended institutes where the author studied gemology in Thailand ... and was happy about his investment!

For those willing to go further after their gemological studies: Recommended Advanced Gemological Courses:

To finish here are some BOOKS about gemology
the author have read and appreciated and would like to recommend to people willing to learn more about gemstones, gemology and the places where gemstones are found:




Creative Commons License

The photos and articles on are licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.
Feel free to use the photos and articles with links and credits. No commercial use without permission.
All the best,



Colombia : The Green Fever Experience

by Jean Baptiste Senoble A.G. (AIGS)
photos by Jean Claude Michelou (ICA)

My first interest in gem mining came when I was 18 years old. I was studying gemology at the ING (Institut National de Gemmologie) in Paris, France, when I viewed a ocumentary about Colombian emeralds produced by Patrick Voillot. The movie piqued my interest in emeralds, and since then it has remained my favorite gemstone. This movie also motivated me to enter further into the world of gemstones.

Soon after, I left to Bangkok, Thailand, where I joined Vincent Pardieu, a French gemologist working (at that time) at the AIGS (Asian Institute of Gemological Sciences) who became my mentor for the past year and half. After finishing my gemological studies at the AIGS, I traveled to Asia and Africa to visit gem mining areas with Vincent. Recently I was able to realize my dream to go to Colombia with the ICA (International Colored Gemstone Association) as Vincent, who is an ICA member, recommended me for this exclusive "ICA mine tour". I was then able to realize my dream and have a ten day field trip to the famous Colombian emerald mines, following the steps of Patrick Voillot.

The vice-president of ICA Jean Claude Michelou, who has lived in Colombia for the past twenty eight years, prepared an exclusive tour, collaborating with local mine owners. The entire tour group consisted of 18 people and included :

Joe Menzie, ICA President
Jean Claude Michelou, ICA Vice President
Emmanuel Piat, ICA Board Director (France)
Benny Bezalel, ICA Ambassador to Colombia
Bryan Pavlik, ICA Ambassador to Austria
Sang Phil Oh, ICA Ambassador to Korea
Andrew Lucas, director of the gemology course development at GIA
Eric Welch, photographer for Gems and Gemology at GIA
Cap Beasley, President of the American Gem Laboratory (AGL)
Glenn Preus, major gem importer, cutter and distributor in USA
Michael Haag, major importer and distributor of emeralds in Europe
Teresa Novellino, editor for the National Jeweler magazine
Mariana Photiou, gem importer in Brazil and USA
Philippe Ballongue, our guide for this travel
As well as John, Susan and William, gem enthusiasts from USA
And me ! A young Frenchman living in Thailand

Our group visiting Bogota

Many members of this group returned with thousands of beautiful pictures. These pictures will be sent to ICA who will publish them in a final report. I will try to share my experience with you using Jean Claude Michelou's pictures in this personal report.

Our trip began in Bogota on 22 October 2005 where we spent three days visiting museums and getting acquainted with the city. At the end of these three days, we were met our guides, seven cars with drivers, and bodyguards all provided by the mine owner Don Yesidh Nieto. Early in the morning, we drived north east to our first destination: The Coscuez mine...

Initially we had planned to visit the mines by helicopter. Unfortunately, bad weather conditions prohibited us from flying, but we were still able to visit all of the mines by SUV. This also allowed us to better enjoy some of the beautiful landscapes of Colombia.

On the way to Coscuez

The road was relatively straightforward until we passed a high mountain range covered in clouds. At this point the road shifted from pavement to dirt, and the temperature started to climb dramatically.

Several hours passed before we arrived at a bridge on the "Rio Minero", which is the famous river found near all famous emerald mines of the Boyaca region. Here I felt like we were really beginning to enter the famous places I dreamed of years ago...

The famous "Rio Minero"

Half way across the bridge all the guards upholstered their weapons and put on their ammunition jackets. Jean Claude told me that it was because this was the landmark approaching the mining areas and there were firm security rules still in place even though the "Emerald War" was long over.

After driving for a few hours on bumpy roads surrounded by high mountains and large valleys, we arrived in Coscuez. Our first stop was the local emerald market named "El Chacaro" which is only open in the morning. From the market I could see the entire valley as well as the former mining area of Coscuez.
This mountain is now half destroyed by dynamite...

Local dealers at the Coscuez emerald market

With the miners from Coscuez

At the market, local dealers showed us nice samples from the area which had a characteristic yellowish green color. The experience also enlightened us to the very high market price of rough material. The government stopped supplying the miners with dynamite approximately a year ago and since then emerald prices have skyrocketed.

A nice emerald crystal from Coscuez, at the "Chacaro" market

Our next stop was at the Coscuez tunnel known as "La Paz". Passing by a small Catholic shrine at the entrance to the tunnel, one person asked the mine manager what quantity of gem quality emeralds they could find in any given month. To answer his question, the manager pointed at the shrine and remarked that only god decides about this.

The tunnel of "La Paz", in the Coscuez area

Entering the tunnel the air became very hot. To aerate the tunnels large plastic tubes following the majority of the tunnel and leading outside have been constructed. Occasionally the tubes are slightly damaged in some spots allowing some air to escape. Encountering a ripped area on one of these tubes allows you a bit of fresh air in an otherwise forbidding environment.

In addition to the dismal atmosphere created by lack of fresh air and boiling temperatures, water infiltration and humidity pose more problems for miners. The miners pump the water out along the same path used to enter the mine. We were surprised by the level of water we had to trudge through during the entire walk. Luckily the mine owners provided us boots before our journey began.

On more than one occasion the mine owners have hired geologists to track the mineral vein in which emeralds are found. The miners follow this vein deep into the heart of the mountain. A major advantage of the Coscuez mining area is that this vein follows a relatively simple linear path so calculating where to dig next is a relatively simple process. As an introduction to this type of mining, this mine was an excellent example of what we would encounter the rest of the trip.

Inside and outside the tunnel of "La Paz", with the miners and the managers

The mining here is completely different from what I have seen in Asia and Africa : we had to walk a kilometer and seven hundred meters into the tunnel to reach the first mining shaft! Finally, we arrived directly above the main tunnel where we encountered an elevator leading down to the production area where remains former emerald pockets and where calcite veins line the walls. Unfortunately, we couldn't see any emeralds there...

ICA members at the elevator of "La Paz",
after a long walk in the tunnel

The next mine on our program was "La Pita" where we arrived mid evening after a long three hours of driving through windy mountain roads. The "La Pita" deposit is very new compared to the ones of Muzo and Coscuez which have already been mined for centuries.

This new deposit was discovered ten years ago and started to produce amounts of good quality emeralds since May 1999. Since then production has decreased as has production throughout the rest of the country. There we were welcomed very generously by the mine owners, who invited us all to stay at their Villa. They gave us free room of their house as well as an access to their swimming pool. This was a uniquely special occasion for me to swim in the very same swimming pool I had previously seen in Patrick Voillot's Colombia documentary.

The "Rio Minero" at "La Pita"

The next morning, we went to see the small local emerald market of "La Pita". The emeralds from "La Pita" are very similar in appearance to the ones from Muzo. They both have a deep highly saturated green color.

After viewing the emerald market, we visited the "La Pita" tunnel. In front of the tunnel entrance there is a small river where I was able to search for some smaller emerald pieces. I was successful in finding two very small pieces.

Searching for emeralds at the entrance of "La Pita" tunnel

ICA members inside
the "La Pita" tunnel

The other important tunnel of the area that we visited is the tunnel known as "Consorcio". The "Consorcio" has a very special story. Miners from the company "Prominas del Zulia" digged the "La Pita" tunnel until it went under the property of another company "Esmeraldas Santa Rosa" where they found the first big pocket of high quality emeralds, which is still producing today.
This violation of territory was a very delicate situation. Fortunately Don Victor Carranza also known as "The Emerald King" in Colombia stepped in and helped finding a compromise before a major conflict could erupt similar to the one that was still ravaging the country fifteen years ago between Muzo and Coscuez. This permitted him to become a shareholder of this mine, where the compromise now split the production evenly between both companies. The "Consorcio" still produce the largest quantity of emerald in the Pita area.

Visit a the "Consorcio" tunnel

At the exit of the Consorcio tunnel bordering the "Rio Minero", we saw independent emerald miners called "guaqueros" who wash the waste of the mine and sometimes find small low quality emeralds called "morallas". In the past when open pit mining was still allowed, the number of the "guaqueros" could reach fourty thousand people.

"Guaqueros" at the exit of the "Consorcio" tunnel, along the "Rio Minero".

Today open pit mining is forbidden, the only remains being tunnels and shafts mined by dynamite and electric hammer. This has reduced the amount of available material for the "guaqueros" to wash causing their numbers to dwindle to a loyal few. We were able to buy some plastic bags from the mine manager which we could fill with this waste from the tunnel. Anything we could find in this waste we were allowed to keep. Some members of our group were able find some nice small specimens.

ICA member checking a rough emerald found by the "guaqueros".

Many others mines are following the "Rio Minero" in "La Pita" area,
such as "Cunas", "El Totumo" and "Polveros" mines.

The "Polvero" tunnel along the "Rio Minero"

Inside the "Polvero" tunnel

After we've visited the tunnels of "la Pita", "Consorcio" and "Polvero", we went to Muzo. We arrived during the evening, after four hours driving. For many years I dreamed of visiting the Muzo sight, so for me arriving in this valley was the most exciting moment of the trip.

On the way to Muzo

The Muzo mining site

Muzo is the only mining site we visited where we didn't had to walk kilometers just to reach the shaft. What sets it apart from the other ones we visited is this one isn't drilled into the side of a mountain. Approaching it, all one can see is a structure with an elevator in the middle. The shaft itself has been worked for many years and its elevator extends very deep into the earth giving access to many different levels. They call this shaft "clavada". The visit was particularly interesting as we could walk many tunnels at different elevations and also experience what it's like to work the rock with electric and hand hammers. Inside the tunnels the air is even hotter than any of the other mines we visited.

The Muzo shaft known as "Puerto Arturo"

Upon leaving the tunnel our guides brought us to a mining area that was once the main emerald source where local miners showed us some nice Muzo emerald samples.

This mountain was mined close to the surface with dynamite, in a method called open pit mining, which has turned the entire mountain into a gigantic pile of rubble. The miners used to push this rubble into the "Rio Minero", which is part of the reason so many "guaqueros" were present at the time open pit mining was still allowed. The government has now placed a strict ban on this type of mining, but we were still able to witness some dynamite explosions there.

Emerald crystal at the former Muzo mining area

After a long morning of hiking through tunnels and rubble, the managers of the mine took us to Don Victor Carranza's house near the mine, where his son Holman invited us for a lunch. Afterward we finally returned back to Bogota.

In Bogota, we were able to visit treatment laboratories, with cedar oil, and polymer resins.

We also had the opportunity to visit lapidary and jewelry workshops, brokerage offices, the Emerald Trade Center building, as well as the Jimenez Avenue where the local emerald brokers make their deals.

Joseph Menzie, the ICA president and Jean Claude Michelou organized three meetings between the ICA group and the owners of Coscuez and "La Pita" mines. One before our departure to the mines, in the house of the ICA Ambassador to Colombia Benny Bezalel, and two after we came back from the mine, one of which was in Don Yesidh house in Bogota.

The ICA President Joseph Menzie, with Don Yesidh Nieto

At these meetings, the mine owners explained to us that they were looking for foreign investors and that they were considering installing a gem laboratory in Bogota if they can find an internationally recognized gem lab willing to install a branch in Colombia. A problem with the emerald industry in Colombia is that many of the mine owners only focus inwardly on production. Many don't realize the importance of international promotion and communication. Joseph Menzie explained them some of the positives an association like ICA can bring them, such as the capacity to communicate with the worldwide gem and jewelry industry, as well as aid them in their projects and in promoting their products image.

A huge matrix specimen

ICA member selecting good quality emeralds

And this is the result of all this industry

I hope this brief field trip report, illustrated by Jean Claude Michelou's pictures, has interested you and gave you a global and realistic idea about the emerald industry in Colombia. I will be also very happy to keep in touch with all the ICA members who were presents after sharing such an experience.

I would like to thank:
ICA, Joseph Menzie and Jean Claude Michelou for organizing us such an unusual trip,
Don Yesidh Nieto and his partners for supporting us during the whole expedition and welcoming us in Coscuez and "La Pita" mines and in his house in Bogota (Thanks also for the shooting experience),
Don Victor Carranza, his son Holman and his partners for welcoming us at the Muzo mine and in his house,
Benny Bezalel for his welcome in his beautiful house as well as in his office in Bogota,
Giovanni Ortiz who permitted us to visit the workshops of Grace's Jewelry and Gems.
Very special thanks goes out also to Philippe Ballongue for guiding us as well as acquainting us with Colombia and just overall making the trip a very pleasant experience.

I finally invite you to read the ICA report about this trip, and the AGTA report as they had also a field trip to Colombia just before us.

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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.