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Figure 1. A fine 925 ct crystal that was formerly displayed in the Texas State Capitol and sat on the governor’s desk in 1969 when the legislature adopted blue Texas topaz as the state gem. This specimen was found in 1904 and now resides in the Hamman Gem and Mineral Gallery in the Department of Earth and Planetary Sciences at the University of Texas at Austin (catalog no. B0344). Photo by Blanca Espinoza.

Topaz from Mason County, Texas

Roy Bassoo, Diane Eames, Matthew F. Hardman, Kenneth Befus, and Ziyin Sun, January 26, 2024

A comprehensive look at Texas topaz, detailing its gemological and compositional characteristics and providing a basis for using trace element concentrations to identify its origin.

Article

Winter 2023 G&G Available Now

Erica Zaidman, January 26, 2024

An overview of the Winter 2023 Gems & Gemology content.

A petrified opalized wood stand supports this marble polar bear.

Occurrence of Petrified Woods in the Russian Far East: Gemology and Origin

Vera Pakhomova, Valentina Solyanik, Dmitrii Fedoseev, Svetlana Y. Kultenko, Vitaliya B. Tishkina, and Valeriya S. Gusarova, October 22, 2020

Scientists in Russia construct an origin story through the analysis of petrified wood popularly used in the souvenir trade.

Figure 1. A silver brooch containing a large Slovak opal (77 ct, 34.5 × 25 × 13 mm) and 48 diamonds. The opal was initially purchased for Louis XVIII’s personal collection. In 1824, it adorned the clasp of Charles X’s coronation mantle, and around 1853 it was remounted onto this brooch for Empress Eugénie, which has been preserved. Photo by Peter Semrád; courtesy of the National Museum of Natural History in Paris (inventory no. MNHN 87.44).

Slovak Opal: A New Life for a Historical Gem

Peter Semrád, January 26, 2024

Reports on the recent production of precious and common opal from a centuries-old locality.

Figure 1. Sedimentary rocks are among the most common rocks exposed on the earth’s surface. This image shows multicolored sandstone layers known as “The Wave” that have been eroded and sculpted by winds to form a swirling pattern of rock strata in the Coyotes Buttes North wilderness area along a portion of the Arizona/Utah border. Photo by Greg Bulla.

Gems Recovered from Sedimentary Rocks

James E. Shigley, Roy Bassoo, and Aaron C. Palke, January 26, 2024

Explores the formation of sedimentary rocks, gems found and formed in sedimentary environments, and the alluvial mining of these gems.

Diamond: Genesis, Mineralogy and Geochemistry, Volume 88 in the Reviews in Mineralogy and Geochemistry series, received this year’s Mary B. Ansari Best Geoscience Research Resource Award.

G&G Contributors Awarded for Best Geoscience Research

GIA Staff, January 26, 2024

Several G&G contributors are recognized for their work on the latest volume in the Reviews in Mineralogy & Geochemistry series.

Texas Topaz, Slovak Opal, a Beryl Inclusions Chart, and More

Duncan Pay, January 26, 2024

An overview of the Winter 2023 Gems & Gemology content.

Cause of Color in Yellow Sapphire, Plus Characterization of Oregon Sunstone, Ukrainian Beryl, and British Columbian Iolite

Duncan Pay, November 3, 2023

An overview of the Fall 2023 Gems & Gemology content.

Figure 1. Mantle eclogite xenolith (2.8 cm in longest dimension) consisting of clinopyroxene (green) and garnet (red-orange), with a partially exposed octahedral diamond. Photo by Annie Haynes. Gift of Mark Mauthner, GIA Museum no. 37511.

Diamondiferous Mantle Eclogite: Diamond Surface Features Reveal a Multistage Geologic History

Matthew F. Hardman and Mei Yan Lai, November 3, 2023

Reports on the analysis of a mantle eclogite xenolith with a partially exposed octahedral diamond.

Figure 12. Rough and cut iolite from Blue Bear. From left to right, the faceted stones weigh 1.24, 0.48, 0.48, and 0.88 ct. Photo by Philippe Belley.

Iolite from the Thor-Odin Dome, British Columbia, Canada: Geology, Chemical Composition, Inclusions, and Cause of Chatoyancy

Philippe M. Belley, November 3, 2023

Reports on the geological setting and gemological properties of violet-blue gem cordierite from new deposits located in British Columbia.

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