Quartz,silicon oxide,is one of the most abundant and ubiquitous minerals in the earth's crust. It is the primary constituent of beach sand and occurs in many colors,all of which are used as gemstones. Amethyst,the most valuable,is the purple variety,and the hue ranges from a pale lilac color ('Rose of France') to a dark,saturated purple with flashes of red ('Siberian amethyst'). The stones pictured range in size from about 3 to 10 carats. Main localities include Brazil,Nigeria,Arizona,Russia,Tanzania and Uruguay | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Arem, Joel |
Taille de l’image : | 3855 px × 2553 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : |
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