Citrine crystals (silicon oxide,formula: SiO2). This mineral is a variety of quartz that is used as a gemstone. Since it is rare in nature it is often obtained by heat treatment of another variety of quartz,the purple amethyst mineral,to produce the orange colour seen. In nature,heat from molten rocks may produce citrines from amethysts | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Biophoto Associates |
Bildgröße: | 3620 px × 2480 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |