Emeralds in a pegmatite host rock. Emerald is a variety of beryl,a beryllium aluminium cyclosilicate. Whereas beryl may vary in colour,emeralds always occur in hues of green,thanks to trace amounts of chromium in the composition. When pure and flawless,emerald is the most precious green gemstone known,the deeper the green the more desirable. This specimen,from Takowaja in the Russian Ural,measures 20 centimetres across | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Wiersma, Dirk |
Taille de l’image : | 3744 px × 4859 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |