The submission of a large (4.54 ct) jeremejevite of an unusual—yellow—color to the AGTA Gemological Testing Center prompted a search of the available gemological literature.

This second major article in a three-dimensional modeling study analyzes fire – the visible extent of light dispersed into spectral colors.

Several gems were recently examined that showed stars with an unnatural appearance or an unusual number of rays.

A comparison study was made between the yellow and white nacre of the gold-lipped Pinctada maxima oyster shell and 65 yellow cultured pearls.

Chinese freshwater cultured pearls (FWCPs) are assuming a growing role at major gem and jewelry fairs, and in the market at large.

Australia’s Argyle mine has set records for volume since its establishment in 1983, and is additionally noted for its rare pink diamonds.

Ammolite is a form of aragonite that is obtained from vivid iridescent fossilized ammonite shells mined in Alberta, Canada.

Gemstone enhancements and their disclosure became the most important gemological issue for the jewelry trade in the 1990s.

The 1990s saw growth in gem exploration, production, and marketing worldwide.

Haüyne is a rare mineral and an extremely rare gemstone.

Two archeological sites that were discovered recently on the island of Antigua appear to have had flourishing lapidary industries.

Since 1996, large quantities of yellow to blue sapphires have been recovered from alluvial deposits derived from basaltic rocks in northern Madagascar.

An investigation of these Yuruty mine samples revealed an interesting new aspect to this bicolored quartz.

Greenish yellow to yellowish green HPHT-treated diamonds exhibited highly saturated body color, well-defined brown to yellow octahedral graining, and visual evidence of heating, among other characteristics.

This study provides detailed mining and gemological information on the Jegdalek deposit, in east-central Afghanistan, which is hosted by elongate beds of corundum-bearing marble.

There has been considerable debate in the gem trade concerning the nucleation procedures being used to grow large round Chinese freshwater cultured pearls.

Several diamonds were treated for the purposes of observation and report with a new laser technique which does not show the typical surface-reaching drill hole.

Results from spectroscopic analyses of GE POL high-pressure high-temperature (HPHT) annealed nominally type IIa diamonds are presented, and these spectral characteristics are compared with those of untreated diamonds of similar appearance and type.

A compilation of gem news from around the world, covering topics such as localities, unusual gem materials, market news, new products, discoveries, jewelry manufacturing techniques, and industry trends.

Lapis lazuli has been mined from the Coquimbo Region of Chile since 1905.