Article Search Results

Show Filters
Showing 10 results for "*"
Abstract Header from the 2009 issue of Gems & Gemology
Abstracts; Summer 2009

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 More

Opal from Querétaro, Mexico: fluid inclusion study

The distinctive orange-to-red “fire" opals from Querétaro have not been found in significant quantities at any other locality.

Read More

Green Opal From East Africa

Gemmological and chemical analysis of bright green gem-quality opal from Tanzania.

Read More

Opals from Opal Butte, Oregon
Opals from Opal Butte, Oregon

Recent mining at Opal Butte in northeastern Oregon has produced a wide variety of large flawless opals.

Read More

Opal from the Shewa Province, Ethiopia

Opal occurs as nodules in volcanic rocks at a new gem opal locality in the Menz Gishe district of Shewa Province, Ethiopia.

Read More

On the Origin of Digit Patterns in Gem Opal

An examination of the finger-like feature mostly found in Ethiopian opal and proposal for its formation.

Read More

Opal from Queretaro, Mexico: Occurrence and Inclusions

An examination of play-of-colour opal from Mexico and its variety of inclusions.

Read More

Treated Andamooka Matrix Opal
Treated Andamooka Matrix Opal

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 More

Queensland Boulder Opal

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 More

Chrysoprase and Prase Opal from Haneti, Central Tanzania
Chrysoprase and Prase Opal from Haneti, Central Tanzania

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 More