2.12 ct Cabochon Cut (12.55 x 9.03 mm) Black Opal Natural Gemstone
Crystal Black Opal - Crystal opal or pure hydrated silica makes up 30% of the opal produced, 8% is black and only 2% is boulder opal.
Black Opal / Lightning Ridge (NSW), Australia by ingrid
Bloodshot Iolite. Known as the gemstone of the Vikings, Iolite was used by Norse and Viking explorers as a navigational aid, as a properly oriented stone would change color in relation to the direction of sunlight, allowing for crude navigation in the fog- enshrouded northern Atlantic waters where the direction of the sun was otherwise impossible to discern.
BRILLIANT "GEM GRADE" BLACK OPAL FROM LR - 3.30 CTS