Larry Tai-An Lai, October 17, 2013
A simple test easily detected dye treatment in fire opal.
Read MoreGrahame Brown, June 1, 1991
Matrix opal from Andamooka, in South Australia, is a precious opal-included porous rock that is commonly colour enhanced (carbon impregnated) to imitate the highly prized black opal from Lightning Ridge in northern New South Wales, Australia.
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