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 | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Wiersma, Dirk |
Bildgröße: | 5616 px × 3744 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |