Richard W. Wise, March 1, 1993
After almost 75 years of inactivity, the deposits of boulder opal in Queensland, Australia, began to attract new interest in the 1960s and 1970s.
Read MoreBrendan M. Laurs, Thomas W. Overton
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.
Read MoreJames E. Shigley, Brendan M. Laurs, and Nathan D. Renfro
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.
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