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Fall 2023 G&G Available Now

Erica Zaidman, November 3, 2023

An overview of the Fall 2023 Gems & Gemology content.

Fire Obsidian’s Beguiling Spectrum

Robert Weldon and Nathan Renfro, August 4, 2023

A look at a rare volcanic glass from central Oregon with lapidary artist Tom Dodge.

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.

Figure 1. A good-quality 88.25 ct “chameleon” amber with a red bodycolor displaying a vivid green fluorescence color that appears to float on the surface. Photo by Yan Li.

The Special Color Effect in “Chameleon” Amber

Jinfeng Yang, Yan Li, and Youzhi Liang, November 3, 2023

An examination of three Burmese chameleon amber specimens using 3D fluorescence spectroscopy.

Nickel-Diffused Spinel, Vietnamese Augite, Brown Mammoth Ivory, and More…

Duncan Pay, August 4, 2023

An overview of the Summer 2023 Gems & Gemology content.

Fancy brownish pink pear and rectangular diamonds, each weighing 0.25 ct, shown in diffused light (A and C) and in long-wave UV light (B and D). Photos by Shiva Sohrabi.

Yellow Zoning in Pink Diamonds

Shiva Sohrabi, Mei Yan Lai, and Sally Eaton-Magaña, August 4, 2023

Unusual natural pink diamonds displaying faint yellow color zoning and strong yellow fluorescence are studied in the Carlsbad laboratory.

Blue Cat's-Eye Apatite

Tao Hsu, March 29, 2013

Deep blue apatite with a cat’s-eye effect, however, is very rare.

Colored Stones Cut with High Precision

Tao Hsu, March 29, 2013

At the AGTA and GJX shows, China Stone (Bangkok) marketed a selection of tiny, precisely cut natural gemstones.

Musgravite from Myanmar

Nathan Renfro, March 29, 2013

Two small, near-colorless stones reportedly from Myanmar (0.11 and 0.24 ct; figure 1) were recently loaned to GIA for examination for identification.

Green Diamond Treated with Radioactive Salt

Marzena Nazz, March 29, 2013

The stone owes all of its green color to these shallow radiation stains.

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