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.
Read MoreA plastic imitation opal that shows true play-of-colour was advertised as "new" and offered for sale under the trade name "Opalite" at the Gem and Lapidary Dealers Association (GLDA) Tucson show in February 1988.
Read MoreGemmological and chemical analysis of bright green gem-quality opal from Tanzania.
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This article, from the Summer 2009 issue of Gems & Gemmology, is a compilation of abstracts of important gemmology-related articles published outside of Gems & Gemmology.
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Commercial quantities of gem-quality chrysoprase and green prase opal (nickel-bearing chalcedony and common opal, respectively) have been recovered from altered serpentinite deposits near Haneti, Tanzania.
Read MoreTwenty-two gem opals from a new volcanic deposit located near Bemia
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