Opal (var. Black Opal)
Australia - Oceania
SiO2•nH2O
Description
Known as "The Desert Rose". Stone shaped like a triangle (31.02 cts) with rounded edges, with a high dome opalized surface consisting of sharply defined small polygonal patches with a strong play of colors mainly red / crimson. The color set is very different depending on the nature of incident light (fluorescent, incandescent or LED) and the angle of incidence, and the red flashes more or less marked.
6 Mile Field, Lightning Ridge, Walgett Shire, New South Wales
Probable extraction year
1973
From the Sanskrit upala, meaning precious stone.
Class
8 - Silicates / Tectosilicates
Dimensions (length x with x height in cm)
2.5x2.5x1
Hardness (Mohs)
5.5
Density (G/cm3)
2
Publication
"Modern Jeweler's - Gem Profile/2 - The second 60"
