Four Treasures Reference Database
Record No. 2079
Black-treated opals
Journal Article
Gübelin, E.J. (1964) Black-treated opals. Gems & Gemology, Vol. 11, No. 5, Spring, pp. 157–159.
ISBN/ISSN: 0016626X | Sinkankas/Born No.: NIS/NIB | RWHL
sugar-treated opal, treatments, gems