Topaz gemstone. Topaz is a neosilicate,an aluminum silicate fluoride hydroxide,chemical formula: Al2.SiO4(F,OH)3. The elongate prismatic crystal habitat can produce a rounded or sharp,diamond-shaped cross-section. This orange-yellow variety is referred to as 'imperial topaz' and considered the most valuable. This unpolished gemstone is from Kabaya in Rwanda. Photographed at the Royal Museum for Central Africa,Tervuren,Belgium | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Wiersma, Dirk |
Taille de l’image : | 3543 px × 5051 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |