Amethyst. The specimen at left is in its natural state,the specimen at bottom right has been polished and the specimen at top right had been cut and polished. Amethyst is a variety of quartz,(silicon dioxide). The purple colour is caused by the presence of compounds of iron or manganese | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Biddle, Paul |
Bildgröße: | 4370 px × 4391 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |