Topaz is an aluminium silicate fluoride hydroxide, chemical formula Al2 SiO4 (F, OH)2. It belongs to the orthorhombic crystal system, with the crystal habitat being slimly prismatic, often with a striated surface. Topaz is found in igneous rocks, like granite and pegmatite, in many places around the world. When clear and without impurities topaz is a popular semi-precious gemstone that comes in a large variety of colours. The specimen seen here is a rough crystal group from a further unspecified locality in Siberia. Actual width is 75 mm | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Wiersma, Dirk |
Taille de l’image : | 5026 px × 3733 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |