The internal structure of opal makes it diffract light; depending on the conditions, in which it formed, it can take on many colors, black is one of the color. Black opal stones will contain reminiscences of common opal which remain intact. Typically, the common opal is strategically placed on the backside of finished black opal stones.
Almost all of the world's supply of black opal is mined from New South Wales and an astonishing 97% of all common opal is sourced from Australia. Other sources for black opal include Ethiopia, but Ethiopian black opal is enhanced through smoke treatment to darken the body tone color.
Hardness 5.5 – 6
Synthetic Black Opal:-
Light-coloured opals can be darkened using several methods to simulate Black opals. - Opal, Lithographie, 2007
Significant Gem Localities:-
Australia:- New South Wales(Lightning Ridge)
South Australia(North West Province)
(Stuart Shelf)
USA:- Nevada(Virgin Valley District)
No comments:
Post a Comment