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June 2023 Birthstone

Pearl: A Gem of Legendary Origins

June Birthstone

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Gemology & Jewelry Design

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SP23 G&G Issue Cover

Montana Sapphire,
Colombian Emerald,
and the 2023 Tucson Report

New Gems & Gemology Issue

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featured

Research & News

Figure 1. Top production from Rock Creek from the 2021 mining season, in rough and cut form. The rough stones range from 10.05 to 67.15 ct and the faceted stones from 3.09 to 12.18 ct. The yellow sapphire at top center was named the Yellowstone sapphire and is part of the Somewhere in the Rainbow collection. For the faceted stones, the blue stone on the left and the two blue stones on the bottom are heated, while the others are unheated. Note that one of the rough stones is missing in the faceted stone layout. Photos by Robert Weldon; courtesy of Potentate Mining, LLC.
Feature

Characterization of Montana Sapphire

Examines the mining history and geological characteristics of the three secondary sapphire deposits in the state of Montana, as well as the properties of these sapphires (unheated and heat-treated).
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Knowledge Session Webinars
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GIA Knowledge Sessions

Engage in webinars on the most diverse and pressing issues in gemology today, including gemstone origin, laboratory-grown stones and new discoveries in field gemology.
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Figure 1. This 2.13 ct purple stone was identified as the rare collector gem anhydrite. Photo by Adrianna Gudino.
Lab Notes

Purple Anhydrite

The Carlsbad laboratory encounters its first example of a transparent purple faceted single crystal anhydrite.
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Figure 1. Rare cloud inclusions were observed in a 0.53 ct D-color diamond. Photomicrograph by Nathan Renfro; field of view 2.39 mm.
Micro-World

Starry Night in Diamond

Cloud inclusions resembling stars at night are observed in a faceted diamond.
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Figure 1. A 4.56 ct rough diamond with plastic deformation lines, highlighted in the sketch on the right. Deformation has occurred along a set of parallel internal slip planes. The planes appear as thin ridges on the diamond’s surface, exposed by natural dissolution of the surface by fluids (i.e., resorption). In fact, the whole surface has been resorbed into this overall dodecahedroid shape, decorated by elongate hillocks and plastic deformation lines, both fine features representing slight interruptions and imperfections in the diamond crystal lattice. Images by Evan M. Smith.
Diamond Reflections

Plastic Deformation: How and Why Are Most Diamonds Slightly Distorted?

A look at plastic deformation, one of the most prevalent features in natural diamond.
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Figure 1. This ring from Graff features a 3.95 ct pink sapphire and 7.5 carats of diamond in a spiral design. Photo by Robert Weldon; courtesy of Jewelerette Co.
Gem News International

Tucson 2023 Overview

An overview of the 2023 Tucson gem shows.
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Gems & Gemology
This Month's

Featured Gems

Featured Gem Peridot
Peridot

Found in lava, meteorites, and deep in the earth’s mantle, yellow-green peridot is the extreme gem.
Fancy Color Diamond
Fancy Color Diamond

Dazzling brilliance. Captivating color. These are the planet’s most valued gems.
Diamond
Diamond

Diamonds are among nature’s most precious and beautiful creations.
Emerald Bluish Green Stone
Emerald

Emerald is the bluish green to green variety of beryl, a mineral species that includes aquamarine.
Featured Gem Citrine
Citrine

Citrine is the transparent, pale yellow to brownish orange variety of quartz.

View the Gem Encyclopedia