![cushion cut spinel from Tanzania](https://www.patrickvoillot.com/wp-content/uploads/2021/03/spinelle-coussin-tanzanie57.png)
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Je vous emmène à travers mes vidéos découvrir mon expérience acquise depuis plus de 30 ans a silloner le globe entier à la recherche de pierres précieuses, de rencontre mémorables mais aussi de difficulté parfois …
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![cushion cut spinel from Tanzania](https://www.patrickvoillot.com/wp-content/uploads/2021/03/spinelle-coussin-tanzanie57.png)
![cushion cut sphalerite from Picos de Europa, Santander in Spain](https://www.patrickvoillot.com/wp-content/uploads/2021/03/sphalerite-coussin-espagne59.png)
sphalerite
Its name comes from the Greek “sphaleros” meaning traitor, deceitful, because in its black variety it looked like galena but did not release lead during fusion … and because of its brightness was also confused with the diamond. It is the major ore of zinc.
![smithsonite cut in cabochon](https://www.patrickvoillot.com/wp-content/uploads/2021/03/smithsonite-cabochon64.png)
smithsonite
Name honoring James Smithson (1765-1829), founder of the Smithsonian Institution in Washington (USA). It is also called bonamite.
![simpsonite from Brazil oval cut](https://www.patrickvoillot.com/wp-content/uploads/2021/03/simpsonite-ovale-bresil68.png)
simpsonite
It was discovered in Australia and its name honors the Australian mineralogist Edward Sydney Simpson (1875-1939).
![yellow - green sillimanite from Tanzania](https://www.patrickvoillot.com/wp-content/uploads/2021/03/sillimanite-tanzanie67.png)
sillimanite
Discovered in 1824, it honors the name of the American geologist Benjamin Silliman (1779-1864). It is also known for its blue or violet variety called fibrolite. It has been known since prehistoric times and it was used to manufacture cutting tools. There is also a
![African serpentine oval cut](https://www.patrickvoillot.com/wp-content/uploads/2021/03/serpentine-taille-ovale-afrique-15.png)
serpentine
Serpentine, or rather the serpentines, is a group of over 20 minerals quite difficult to differentiate the one from the other, the best known of whom are : antigorite, chrysotile and lizardite. These Phyllosilicates are weathering products of magnesium silicates. The Ophite, sometimes called “ophite