Winter 2023 - Volume 59, Issue 4
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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

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

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Figure 1. Various negative crystals in pink sapphire from Sri Lanka (A, enlarged in B) and fingerprints in blue sapphire from Burma (C, enlarged in D). Image B shows bubbles in flat negative crystals, and the center negative crystal in D has a bubble. Photomicrographs by Momo Matsumura (A and B) and Shunsuke Nagai (C and D); fields of view 4.05 mm (A), 8.15 mm (B), 8.47 mm (C), and 1.71 mm (D).
FTIR Identification of Carbon Dioxide Fluids in Sapphire

FTIR spectroscopy shows that the existence of carbon dioxide gas bubbles in a negative crystal in sapphire is no longer proof of the absence of heat treatment.

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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

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

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Figure 1. <em>Pinctada radiata</em> shell with a natural blister pearl measuring approximately 11.39 × 9.31 × 8.69 mm. Photo by Gaurav Bera.
An Unusual Partially Non-Nacreous Pinctada radiata Natural Blister Pearl

A large Pinctada radiata natural blister pearl displays a unique reaction under long-wave ultraviolet light.

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Figure 1. An omphacite jade pendant measuring 68.4 mm tall, shown in reflected light (left) and transmitted light (right). Photo by Tsung-Ying Yang.
A Unique Omphacite Jade Pendant

A carved jade pendant displaying both dark green omphacite and paragenetic yellow vesuvianite is examined.

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Figure 1. Left: Black beryl beads displaying six-rayed stars. Right: Black beryl beads displaying twelve-rayed stars. Photos by Tinh Xuan Nguyen.
Star Beryl

Black beryl beads display six-rayed and twelve-rayed stars.

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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

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

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Figure 2. The cut and polished piece of pyritized triceratops fossil on the left weighs 50.5 ct and measures 41.28 × 22.23 mm. The piece on the right weighs 22.5 ct and measures 31.75 × 15.88 mm. Photos by SD Gem & Fossil.
Pyritized Triceratops Fossils from South Dakota

A newfound dinosaur site in the Hell Creek Formation of South Dakota leads to the discovery of pyritized triceratops fossils.

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Figure 1. The “Infinite Blue,” an 11.28 ct Fancy Vivid blue diamond, sold for $25.3 million in Hong Kong. Courtesy of Sotheby’s.
Fall 2023 Auction Highlights

Large blue and pink diamonds were among the top lots of the fall auction season, including the most expensive auction jewel of 2023.

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Figure 1. Artisanal mining in Liberia. Courtesy of Diamonds for Peace.
Artisanal Diamond Mining: Addressing the Knowledge Gap

Diamonds for Peace conducts basic training on rough diamond grading for artisanal miners in Liberia.

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