Opal is an amorphous hydrated silicon oxide, chemical formula Si02.nH20. It is precipitated from silica-bearing waters in voids and fissures of certain rocks. Water molecules trapped in the silica framework account for the milky lustre and brilliant pastel colours that make opal such a desirable precious stone. Specimen is from Opal Butte, Oregon, USA and actual width is 75 mm. | |
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 |
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