| Gewicht | 0,492 kg (492 gr) |
|---|---|
| Dimensions | 7 × 7 × 7 cm |
| Sales Unit | |
| Type | |
| Form | |
| Origin | |
| SKU | 20957 |
Green Opal Sphere
Sales unit: Unique
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Green Opal Sphere from Madagascar
Opal
Opal is an amorphous form of silica with variable water content. Within opals, a distinction is made between precious opal, which is known for its play of colours (opalescence), and ordinary opal, which does not show this effect. Common opal occurs in various colours such as white, pink, blue, green or brown, usually with a waxy to glassy luster.
Major deposits include Australia, Peru, Mexico, Brazil and the United States. Its chemical formula is SiOâ‚‚-nHâ‚‚O. Common opal often forms in volcanic or sedimentary environments. Its hardness is between 5.5 and 6.5 on the Mohs scale.
Well-known varieties include pink Peruvian opal, green opal, Black opal and dendritic opal, which are distinguished by their unique colour and inclusions.
Sources:
Mindat.org, Gemdat.org, Wikipedia - Opal
