An opal rough is immersed in water and treated with oil and Opticon to observe effects on transparency and play-of-colour.
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The first documented UV-reactive chemical treatment to make opal appear tenebrescent.
Read MoreThis section, from the Summer 2012 issue of Gems & Gemmology, is a compilation of interesting finds from GIA’s laboratories.
Read MoreThis section, from the Summer 2007 issue of Gems & Gemmology, is a compilation of interesting finds from GIA’s laboratories.
Read MoreThis section, from the Summer 2003 issue of Gems & Gemmology, is a compilation of interesting finds from GIA’s laboratories.
Read MoreThis section, from the Summer 1987 issue of Gems & Gemmology, is a compilation of interesting finds from GIA’s laboratories.
Read MoreThis section, from the Summer 1986 issue of Gems & Gemmology, is a compilation of interesting finds from GIA’s laboratories.
Read MoreThis section, from the Summer 1985 issue of Gems & Gemmology, is a compilation of interesting finds from GIA’s laboratories.
Read MoreThis section, from the Summer 1983 issue of Gems & Gemmology, is a compilation of interesting finds from GIA’s laboratories.
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