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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.

Figure 1. Chalcedony petrified tree fern is carved as an ornamental gem material. This 60 × 40 mm dragon carving has a uniform texture and bright color. Photo by Hai-Long Wang.

A Unique Petrified Tree Fern from Northeast China

Ying Yan, Xiao-Yan Yu, Han-Yue Xu, and Zhi-Rong Xie, January 26, 2024

Documents the gemological properties, chemical composition, and appearance of petrified tree fern discovered in northeast China.

An Early Byzantine Engraved Almandine from the Garibpet Deposit, Telangana State, India: Evidence for Garnet Trade Along the Ancient Maritime Silk Road

H. Albert Gilg, Karl Schmetzer, and Ulrich Schüssler, August 6, 2018

Analyzes the chemical composition and inclusion characteristics of this ancient artifact.

Figure 1. Lidded goblet from the collection of the Bavarian National Museum in Munich, embellished with red Bohemian garnets. Inventory no. 60/74, height 17.7 cm. Photo by Bastian Krack; courtesy of Bavarian National Museum in Munich.

Bohemian Garnets as Decorative Materials for Glass Vessels from the Late Sixteenth to Early Eighteenth Centuries

Karl Schmetzer, Hans Albert Gilg, and Hans-Jörg Ranz, January 26, 2024

Examines a technique for setting cut garnets on glass objects, invented by Claudius vom Creutz of Nuremberg in the late sixteenth century.

Figure 1. Demantoid garnet (0.84 ct on the left and 0.28 ct on the right) and an orange grossular garnet (0.55 ct) from Sonora, Mexico. Photo by Diego Sanchez.

Demantoid, Andradite, and Grossular from Mexico

Aaron Palke, January 26, 2024

A look at new gem material from the iridescent andradite deposit in Sonora, Mexico.

The newly discovered variety of amblygonite-montebrasite is unique for its blue color. It often has a mottled appearance with alternating blue and creamy white patches. The faceted stone weighs 0.83 ct. Photo by Lhapsin Nillapat.

Blue Amblygonite-Montebrasite from Rwanda

Wim Vertriest, Gil Yuda, and Joe Henley, January 26, 2024

A report on a new blue variety of amblygonite-montebrasite from Rwanda.

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

Duncan Pay, January 26, 2024

An overview of the Winter 2023 Gems & Gemology content.

Article

Fall 2023 G&G Available Now

Erica Zaidman, November 3, 2023

An overview of the Fall 2023 Gems & Gemology content.

Figure 1. These exceptional natural yellow sapphires from Madagascar (2.1–2.6 ct) represent both the Fe<sup>3+</sup> chromophore and the trapped hole paired with Fe<sup>3+</sup>. Photo by Ronnakorn Manorotkul/Lotus Gemology; courtesy of GemFever.

Yellow Sapphire: Natural, Heat-Treated, Beryllium-Diffused, and Synthetic

John L. Emmett, Ungkhana Atikarnsakul, Jennifer Stone-Sundberg, and Supharart Sangsawong, November 3, 2023

Investigates the various chromophores responsible for color in four types of yellow sapphire.

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