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Figure 1. The deep colors of green and brown augite from Dong Nai, observed in transmitted light. Top: The 9.78 g rough on the left yielded a 24.20 ct carving (24.99 cm in height). Bottom: The 11.22 g rough on the left yielded a 56.10 ct carving (36.50 cm in height). Photos by Le Ngoc Nang.

Gem-Quality Augite from Dong Nai, Vietnam

Le Ngoc Nang, Lam Vinh Phat, Pham Minh Tien, Pham Trung Hieu, Kenta Kawaguchi, and Pham Minh, August 4, 2023

Offers a comprehensive look at a variety of augite from Dong Nai, Vietnam, detailing its formation and gemological characteristics.

Figure 1. An 11.68 ct treated phantom opal in which the phantom structure appeared during experiments with various solutions. The sample is shown under daylight through the dome (left) and under halogen lighting through the bottom (right). Photos by Le Ngoc Nang.

A New Treatment: Creating Phantom Structure in Opal

Le Ngoc Nang and Pham Minh Tien, August 4, 2023

A newly developed treatment creates a phantom structure in opal visually similar to natural phantom opal.

Figure 1. Greenland’s rubies are characterized by abundant twinning planes. The twinning planes are not altered by the treatment at a larger scale, but features associated with the twinning can be significantly affected by heating. Photo by S. Wongchacree; field of view 14.40 mm.

Characteristics of Treated Rubies from Greenland

Martin Viala, Wim Vertriest, Charuwan Khowpong, and Suwasan Wongchacree, August 4, 2023

An overview of the treatment process of ruby and pink sapphire from Greenland and its effect on inclusion scenes and chemistry.

Figure 1. A strand of baroque-shaped freshwater bead cultured pearls shown with two <em>Tridacna</em>-species mollusk shells from GIA’s shell reference collection. Each sample weighs approximately 20 ct, ranging from 16.73 × 12.58 × 12.49 mm to 18.98 × 13.53 × 13.43 mm. Photo by Nuttapol Kitdee.

Saltwater Clamshell Beads (Tridacna Species) Used in Freshwater Cultured Pearls

Kwanreun Lawanwong, August 4, 2023

A report from GIA’s Bangkok laboratory on freshwater bead cultured pearls with saltwater bead nuclei.

Figure 1. The cream-colored pearl weighing 0.23 ct and measuring 3.20 × 3.12 mm, shown against the anterior of a <em>Pinctada radiata</em> mollusk. Photo by Nuttapol Kitdee.

An Unusual Metallic Core in a Natural Pinctada radiata Pearl from Kuwait

Ravenya Atchalak, Kwanreun Lawanwong, Emiko Yazawa, and Abeer Al-Alawi, August 4, 2023

Examination of natural pearls from Kuwait reveals one with a suspected metal oxide at the core.

Figure 1. This 29.60 × 23.84 × 18.35 mm cluster of well-formed isometric fluorite and monoclinic geocronite crystals was recently discovered at the Milpo mine in Peru. Photo by Annie Haynes.

Quarterly Crystal: Geocronite in Fluorite

John I. Koivula and Nathan Renfro, August 4, 2023

A cluster of well-formed fluorite and geochronite crystals was recently discovered in Peru.

Figure 1. A 30.80 ct faceted quartz containing pinkish orange inclusions. Photo by Hongtao Shen; courtesy of Jinrui Dong.

Triplite Inclusions in Quartz from Yaogangxian, China

Qian Zhang, Xingtong Li, and Hongtao Shen, August 4, 2023

Pinkish orange crystal inclusions in a faceted quartz are identified as the rare phosphate mineral triplite.

Pink Zektzerite

Jamie Price, August 4, 2023

A rare example of faceted gem-quality zektzerite is examined in GIA’s Carlsbad laboratory.

Figure 1. An imitation emerald in the form of a chess knight measuring approximately 35.05 mm in height. Photo by Kristin Reinheimer.

Plastic Imitations of Emerald

Emily Jones and Abadie Ludlam, August 4, 2023

Two items submitted as emerald to the New York lab are identified as plastic manufactured products.

Four non-bead cultured pearls (samples 1–4, left to right) weighing 0.22 to 4.84 ct. Photo by Gaurav Bera.

Fine Linear Structures in Non-Bead Cultured Pearls

Gauri Sarvankar, Abeer Al-Alawi, Karan Rajguru, and Roxane Bhot Jain, August 4, 2023

Analysis of internal structures in non-bead cultured pearls submitted to GIA’s Mumbai laboratory.

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