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.


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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)

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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,


The "Corby" Ruby Mine,
Baringo region, Kenya

Text by
Vincent Pardieu (Gubelin Gem Lab, Lucerne, Switzerland)

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

The 2005 and 2007 expeditions were supported by the Gubelin Gem Lab located in Luzern, Switzerland, as the 2005 expedition was financed by the Gubelin Gem Lab and the AIGS Gemological Laboratory in Bangkok, Thailand and, because at the time of the 2007 expedition the author was working at the Gubelin Gem Lab as a gemologist.

Presentation of the Baringo/Bogoria Ruby deposit:

Rubies and pink sapphires were told us to have been first reported in the Baringo/Bogoria area in June 2001 from the Barsemoi area in the south west of Lake Baringo and the Kurendoi area in the north east of Lake Bogoria. The deposit is magmatic but I prefer to say that the rubies are "basalt related" as it is not clear if the rubies were formed in the magma or where just transported by this magma the later been the more likely I feel that the term "basalt related" is more suitable. Rubies are found in eluvial/alluvial deposits in small basins down the volcanic hills composed mainly of olivine basalts probably from the Miocene age.

We visited this region during summer 2005: At Barsemoi we were not able to reach the mines and were just able to see few stones from local dealers. At Kurendoi, we managed to have a 2 days visit at the Corby company operation while the company was just starting mining. One month after, on the way back from Tanzania, we were able to see and study rapidly the product of the first weeks mining: A 3 kilograms parcel of rubies.

Most of the stones from Baringo we saw were pink to pinkish red in color, a color evocating more the flamingos from the area than the "raw meat red" of the Tsavo ruby cabochons. They were mostly flat and their size was going from 0,5 to about 20 carat rough. A large number of stones were transparent gem quality as you can see on the following photos. The stones from Baringo area were reminding the aspect of the Thai Cambodian rubies found around Trat, Chanthaburi, Pailin and Samlot. The main difference between the rubies from Thailand and Cambodia and those from Baringo is that that globally Baringo rubies are more on the pink side compared to their well known Thai / Cambodian cousins.

The purpose of these expedition to the Baringo ruby deposit was to collect data for gemological research purpose regarding origin determination of rubies. Origin determination of gemstones is an important part of the daily work at the Gubelin Gem Lab where the author is an employee. To maintain our capacities at their best level regarding origin determination, it is important to keep our reference stone collection up to date and to collect data at the source.

1) Introduction:

We invite you to follow our winter 2007 field trip to the Mergui pearl farms 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 literature. 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 expeditions and explore East Africa downloading the placemarks we prepared.
Just download them clicking on the icon on the left to fly to Kenya and Tanzania

The Baringo and Bogoria lakes of Kenya are world wide famous for their millions of flamingos while the highlands around the lakes are famous for their men which are among the best Kenyan Marathon runners:
We visited this region during summer 2005. The mining area at Kurendoi was difficult to access due to the swampy areas around Lake Bogoria and their muddy tracks and the very steep volcanic hills it was necessary to pass to reach the mine. A challenge for our driver despite his good car, but a small adventure in comparison with the year it took to the Corby company to build through these beautiful volcanic hills the road to the mines.
A view over the brand new Corby mining camp during July 2005. Behind the camp lies the Weseges river and the new road linking the mine to the world. The main problem mining in this area is the water supply. From Oct 2005 to April 2006, the Weseges river was dry and mining had to stop.

Rubies Nittin Patni, manager of the Corby ruby mining operation presenting us proudly his ruby washing plant. Such machines were commonly used in Thailand were water supply was not a problem but in drier region like Kenya mining with such machinery is only possible when water is present to turn the gem gravel into mud and use gravitation to separate rubies from the ground.

The author study the heavy machinery bring by Corby to work the Baringo elluvial/alluvial deposit at Kurendoi.

After a visit of the mine which was preparing for some serious mining we decided to go to the surrounding hills to prospect a little the area as the day before some rain washed the area. A very good occasion to search and collect some rubies and minerals on the floor.
Jean Baptiste Senoble studying and collecting pieces of Basalt on the hills. The collect was not without danger as many scorpions were found resting under the pieces of basalt lying on the floor.
Details on some samples of Olivine basalt collected on the volcanic hills around the Corby mine at Kurendoi.
Here is what we were looking for: Small "Baringo rubies", they are visible on the floor as the rain washed out the dust. On the hills in Baringo area like as in many other basalt related ruby and sapphire deposits, the rain is welcome as it reveal gems.

If rubies are found commonly on the ground on the hills around the mine, it is more rare to find rubies still attached to the basalt. These samples were collected by people from the Corby operation and presented to me in October 2007 in Nairobi as I visited their Nairobi office. I was not very surprised to see these specimens as I found similar rubies and sapphire in basalt on several occasion during my numerous visit in Pailin, a Cambodia.
It is nevertheless interesting to say here that even if this subject is still controversial among geologists, these rubies were probably not formed in the basalt, but they were transported in the lava that turned to basalt when it was bring to the surface by the volcano. It means that they are possibly better described as "basalt related" than magmatic or basaltic. The melted aspect of the surface of the rubies result probably from the corrosion these gems experienced when they were transported in the magna.

Here are now several parcel of Baringo rubies mined at Kurendoi.
On the two following photos you can discover several rubies we saw while meeting gem dealers returning from the Barsemoi area. Sadly we were not able to visit the mines due to the recent heavy rains. At Barsemoi we were told that the mining was performed by local people collecting stones from the ground using simple tools and no machinery. It was interesting to see these stones from Barsemoi are looking globally more orange compared to the pinking purplish stones we saw from Kurendoi.

ICA Ambassador to Kenya, Suzie Kennedy presenting to us a large parcel of Baringo Rubies from the Corby operation at the end of August 2005: The result of the three first weeks of mining.


October 2007 update about ruby mining at Kurendoi: After few months of operation, the mining at Kurendoi, Corby stopped mining from October 2005 to March 2006 due to the lack of water. After the return of the rain and one month of intense preparation a new mining campaign started in May 2006 but mining had to stop after few days due to a conflict with the nearby villagers. The Kenyan press was reporting regularly about this conflict in 2006 and 2007. At the time of my last visit in Kenya in October 2007, the conflict was not yet solved and the Corby company was not able to start again mining. Nevertheless we could see in Nairobi and even Arusha some small quantities of Baringo rubies. People from the Corby company told us that local people were illegally mining the area which explain that Baringo rubies are still present in small quantity in Nairobi gem market.

Brief gemological properties of Rubies from the Baringo area, Kenya:

Color: Pink to pinkish purple
Refractive Index:
Ne=1.759 to No=1.766 to 1.774
Birefringence: -0.007
Specific Gravity: 3.95
Dichroism: Pinkish Purple to Pinkish Orange
Optic Sign: Uniaxial Negative
Chealsea Filter: Reddish
SWUV: None to weak red
LWUV: None to faint red
Origin of Color: Cr
Inclusions: Twinning, intersection tubes, melted crystals with equatorial hexagonal iridescent platelets or "decrepitation haloes", very thin rutile needles, particles,

The most distinctive inclusion in Baringo rubies are the numerous minute melted crystals hosting in their center a frosted bubble (visible using bright field illumination like in the following photo) and associated with an equatorial hexagonal iridescent platelet very visible using fiber optic illumination with the right angle like in the previous photo.

An interesting inclusion also found in Baringo rubies are very thin short rutile needles as you can see on the following inclusion photo (using fiber optics) and the next one (using dark field illumination) where we can see the needles intersecting at 60/120 degrees. This is interesting as rutile needles are not commonly seen in other basalt related rubies from Thailand or Cambodia.

Another interesting inclusion commonly seen in Baringo rubies are twinning planes associated with intersection tubes as we can see in the two following photos taken using cross polars illumination:

In the following photo we can see the intersection tubes associated with the twinning planes and the decrepitation haloes and other thin films in a Baringo ruby using dark field illumination and partially fiber optics.

Notes about the Kenya gemstone mines pages (Edited on Oct 10, 2008)

These "Gemstone mines of Kenya" web pages presents the result of the two gemological expeditions to East Africa in Jul. and Aug. 2005 and Oct. 2007. They were build with the support of ICA (The International Colored Stone Association) and particularly of ICA ambassador to Kenya Suzie Kennedy and her husband Kennedy Khamwati for the Kenya part. Kennedy was nice enough in 2005 to take us to visit all the ruby and tsavorite mines we wanted to visit. His help, presence and permanent support was highly appreciated. In Oct 2007 we were helped in the field by ruby and tsavorite miner and ICA member Genson Micheni Musa, the owner of the Tsavolite mine near Tsavo. Micheni support was also very much appreciated.
I want here to dedicate these pages to Kennedy and Micheni as without them I would not have been able to collect and share all these notes about gem mining in Kenya.

The Jul. and Aug. 2005 expedition was a join expedition by the AIGS gemological Laboratory in Bangkok, Thailand (where I was then the Laboratory Director) and the Gubelin Gem Lab, in Lucerne Switzerland. I was then traveling with Jean Baptiste Senoble, one of my former AIGS gemology student, working as I write these words in 2008 for Nomad's Co Ltd, a Bangkok based gem dealer.

The Oct 2007 expedition was also part of a larger expedition to East Africa I lead in collaboration with gemologist Richard W. Hughes. I was then gemologist for the Gubelin Gem Lab. Two young gemologist and former AIGS students: Guillaume Soubiraa and Michael Rogers joined me in this expedition as well as One of Guillaume Soubiraa friends from Madagascar: Philippe Brunot.

The purpose of these expeditions was to visit ruby, sapphire, alexandrite, emerald, tsavorite, tanzanite and tourmaline mines in Kenya and Tanzania for gemological research purpose. Origin determination of gemstones like rubies and sapphires is an important part of the daily work at the Gubelin Gem Lab and it is important for a gemologist specialized in origin determination of gemstones to collect data directly at the source in order keep his knowledge of the world gemstone mining areas updated. As a former tour guide, turned into a gemologist, it is my pleasure to share the benefit of these expeditions with you and I hope that it will benefit to the people who welcomed and helped us in the field.

Please visit the other Kenya pages on

1 a) Kenya, a Gemstone safari: Kenya main page

1 b) Kenya, Summer 2005 expedition report.

2) On the way to Tsavo: The Simba ruby mine:

3 ) Tsavo, Mengare Swamp: The "Rockland" (former "John Saul") ruby mine.

4 ) Tsavo, Mengare swamp: The "Aqua" (former "Penny Lane") ruby mine.

5 ) Tsavo, Mengare Swamp: The "Equator" ruby mine.

6) Tsavo, Mengare Swamp: The "Hard Rock" ruby mine.

7) Spinels from Kasigau:

8) The Tsavolite Tsavorite mine:

9) The Bocrest Tsavorite mine:

10 ) The Nadan Tsavorite mine

11) The Baraka Tsavorite mine

12) The Scorpion Tsavorite mine

13) Color change garnets:

14) The Baringo ruby mine

Special thanks,
to all the Kenyan authorities we met which provided us support and help, to the miners who welcomed us at their mines, shared with us their time and their life. Your support and welcome was much appreciated!
I hope that this report will be useful to all people we met in Kenya and to all the people interested in the gem trade from the production areas in Kenya 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 these expeditions to Kenyia, I would not have succeded in these expeditions:

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

Jean Baptiste Senoble currently working for the Nomad's company in Bangkok was my gemology student at the AIGS, in Bangkok and became then one of my regular traveling companions to gem markets and mines around Bangkok. He was my traveling assistant during the 2005 gemological expeditions to Vietnam, Sri Lanka, Madagascar, Kenya and Tanzania. We returned together in Tanzania and Madagascar in 2008. Without his help and support these expeditions would not have even been possible.
All the best to you JB!

Guillaume Soubiraa (from SMDA in Madagascar) and Mike Rogers, two former students of the AIGS in Bangkok and Philippe Brunot, one of Guillaume childhood friends from Madagascar were my travelling companions while visiting Kenyan ruby and tsavorite mining areas in October 2008. Thanks to their presence, support and presence this expedition turned to be a pleasure and a success.

All the best guys and great thanks!

These 2005 and 2007 expeditions to Kenya tsavorite and ruby mines would not have been possible without the help of local members of the Kenyan gem trade:

Suzie Kennedy is the current ICA Embassador to Kenya. With her husband Kennedy Khamwathi, they are some very active members of the Kenyan gem trade. Our 2005 and 2007 expeditions were possible thanks to their help and support.

The presence of Kennedy each day during all our 2005 expedition was very much appreciated and so useful to the succes of this expeditions.
Really thanks to both of you!

Genson Micheni Musa is a Kenyan ruby dealer which turned into a tsavorite miner in Kasigau area. His mining company "Tsavolite" is located just near the famous Tsavo National Park. Micheni was a wonderful and fiendly guide during our October 2007 expedition. His knowledge of the Kenyan gem trade and of the Tsavo area was very useful to the success of our expedition.
Thanks Micheni!

Finally I don't want to forget to thanks the Gubelin Gem Lab in Lucerne, Switzerland, my fellow gemologists and colleagues working there for their support in the realization of this expedition.

Interesting Links and recommended readings about gemstones from Kenya:

"Gemstones and Jewelry in Kenya, 2005" from the Kenyan EPZA "Export Processing Zones Authority"
"The mineral industry of Kenya and Uganda, 2002" by Thomas R. Yager
"The mineral industry of Kenya, 1998" by Philip M. Mobbs
"Geology of sapphire and ruby deposits - The example of the John Saul Ruby Mine, Mangare, Kenya": The PHD thesis of Dr Cedric Simonet. A must to read work for those interesting in Kenyan ruby and sapphire deposits.
"General setting of coloured gemstone deposits in the Mozambique Belt of Kenya" and other publications about gem deposits in Kenya on Cedric Simonet's website.
"Geology and gem deposits of Kenya"
"The Kimbo ruby deposit": An excellent study of the John Saul mine by Dr Cedric Simonet, a former manager of the mine for Hard Rock Mining.
"The John Saul Ruby mine": On Swala Gem Traders website, an interesting article about the discovery of rubies in Tsavo by American geologist John Saul.
"Savanna rubies ": by Creative Gems, an interesting attempt to brand rubies from Tsavo.
"With Open arms" A Kenyan farmer found precious bounty in his barren fields. By Denis Maina Gathanju
"Kyanite mining in Kenya", Touchstone mining company
"Star sapphire from Kenya", N.R. Barot, A.Flamini, G.Graziani, E.J. Gubelin, Journal of gemmology, 1989,21,8
"A new sapphire deposit, Turkana, Kenya", T. Themelis, Gemological Digest, Vol.2,No.4,1989
"The Growth of rubies in south -east Kenya" R.M. Key and J.O. Ochieng, Journal of Gemmology,1991,22,8
"Pink sapphire from Kitui, Kenya", Dr N.R. Barot and Dr R.R. Harding, Journal of gemmology,1994,24,3
"Golden tourmaline from Kenya" Gems and Gemology, Summer1996, pp135-136
"Kenya, a mining journal supplement, 2007" by Mining Communications Ltd 2007, London
"Colour-changing chromiferous tourmalines from East Africa" Prof. Dr H. Bank, Dr U.Henn, Journal of gemmology, 1988,21,2,pp.102-103
"Chemical fingerprinting of some East African gem rubies by Laser Ablation ICPMS" A.H. Rankin, J. Greenwood, D. Hargreaves, Journal of gemmology, 2003,28,8,pp.473-482
"Geology of the Yellow mine (Taita-Taveta district, Kenya) and other yellow tourmaline deposits in East Africa" Dr.C.Simonet, Journal of gemmology, 2000,27,1,pp.11-29
"Kenyan rubies exported to Thailand", Gems and gemology, Winter 1986, p.247
"Update on ruby output in Kenya", Jewelry News Asia, No170, October 1998, p.63
"An update on the John Saul ruby mine", Gems and gemology, Winter 1999, pp.213-214
"Exotic origin of the ruby deposit of the Mangari area in SE Kenya" A.Mercier, P.Debat, J.M. Saul, Ore Geology reviews, Vol.14,1999,pp.83-104
"The Dusi (Garba Tula) sapphire deposit, central Kenya - A unique Pan African corundum-bearing monzonite" C.Simonet, J.L. Paquette, C.Pin, B. Lasnier, E. Fritsch, Journal of African Earth Sciences, Vol.38,No.4,2004,pp.401-410
"Un grenat vert: la tsavorite" S. Heppe, Revue de gemmologie AFG, No.99,Juin 1989,pp.5-7
"Tsavorite, une pierre Africaine", V.Pardieu, Revue de gemmologie AFG, No154, Decembre 2005, pp.8-11
"Les tourmalines magnesiennes d'Afrique de l'Est", C.Simonet, Revue de gemmologie AFG, Septembre 2006, pp.4-7
"Le grenat vert tsavorite: Presentation et debat", C. Bridges, Revue de gemmologie AFG No161, Septembre 2007, pp.4-7
"Saphirs et rubis, Classification des gisements de Corindon", Le Regne Mineral, No.55, Jan-Fev. 2004
"The ICA 2006 World Colored Gemstone Mining Report", InColor, Spring 2006
"Rubin, Saphir, Korund, Schon, Hartselten, kostlar", extraLapis No15, 1998

Interesting Books about Gemstones from Kenya:

"Gemstones from East Africa" by Peter C. Keller (1992)
"Ruby and Sapphire" by Richard W. Hughes (1997)

Interesting links and bibliography about Flamingos from Baringo and Bogoria lakes:

"Flamingos from Lake Bogoria" by National Geographic


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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.