Tourmaline crystals (green) in quartz. Tourmaline is a boron-silicate mineral that forms crystals that are straight elongate prisms. It occurs in a number of colours,some of which are much sought after as semi-precious gemstones. This specimen,from Minas Gerais,Brazil,is 25 centimetres wide | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Wiersma, Dirk |
Taille de l’image : | 5616 px × 3744 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |