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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. The color zoning in this 3.57 ct almandine garnet creates a cross structure that forms three-arm trapiche patterns at every intersecting point of the crystal. Photo by Le Ngoc Nang.

Trapiche Garnet from Vietnam

Le Ngoc Nang, Ho Nguyen Tri Man, and Pham Minh Tien, January 26, 2024

A rare occurrence of 14 trapiche patterns is observed in a garnet sample from Vietnam.

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.

Article

Fall 2023 G&G Available Now

Erica Zaidman, November 3, 2023

An overview of the Fall 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.

This iridescent ferropericlase crystal with a stress halo measuring approximately 0.7 mm was trapped inside a light brown diamond. Photomicrograph by Kyaw Soe Moe; field of view 1.58 mm.

Iridescent Inclusion in Brown Diamond

Kyaw Soe Moe, November 3, 2023

An iridescent crystal with a stress halo is observed in a light brown diamond.

This etch channel seen in the crown facets of a 1.00 ct diamond with SI<sub>1</sub> clarity (left) resembled a <em>gada</em> (right), a mace-like weapon wielded by the Hindu god Hanuman. Photomicrograph (left) by Deepak Raj; field of view 0.80 mm. Photo (right) courtesy of the Metropolitan Museum of Art.

Inclusion Resembling a Gada in Diamond

Rujal Kapadia, Bhavya Maniar, and Sally Eaton-Magaña, November 3, 2023

An etch channel in the crown facets of a diamond resembles a mace-like weapon.

A well-formed colorless breyite crystal reminiscent of a stone making a splash in water. Photomicrograph by Aprisara Semapongpan; field of view 1.07 mm.

Breyite in Diamond

Aprisara Semapongpan, November 3, 2023

A colorless transparent crystal inclusion in diamond is reminiscent of a stone splashing in water.

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