November 2024 Birthstone

Falling for Topaz and Citrine

November Birthstone

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FA24 GG Issue Cover

Fancy Cut Grading, Machine Learning, and GenAI for Jewelry Design

New Gems & Gemology Issue

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featured

Research & News

Hand holding demantoid garnet rough in matrix.
Field Gemology Update

The Latest in Field Gemology from Wim Vertriest

Learn the latest on Madagascar sapphires and demantoid garnets from Wim Vertriest, GIA Manager of Field Gemology.
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Figure 1. Oval-, pear-, and marquise-shaped diamonds show more complex appearance patterns than standard round brilliants. Photos by Jian Xin (Jae) Liao.
Feature

Observations of Oval-, Pear-, and Marquise-Shaped Diamonds: Implications for Fancy Cut Grading

Presents findings from observations of oval-, pear-, and marquise-shaped diamonds, laying the groundwork for a fancy cut grading system.
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Figure 1. These seven stones (0.24–1.44 ct) ranging in color from yellowish green to bluish green were identified as the rare gem haüyne. Photo by Annie Haynes.
Lab Notes

Green Haüyne

A suite of seven rare haüyne stones are examined in the Carlsbad laboratory.
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Figure 2. This opaque black hematite inclusion in one of the quartz spheres is composed of numerous platy inclusions arranged in the shape of a rose. Photomicrograph by Nathan Renfro; field of view 2.40 mm.
Micro-World

“Rose” Quartz

Examination of rock crystal quartz spheres reveals rose-like hematite inclusions.
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Figure 4. Peering inside a natural diamond can give scientists an unparalleled perspective into the earth’s interior. Diamonds capture a lasting record of deep mantle processes over billion-year timescales, making them a unique window into geological space and time. Image created using Adobe Photoshop Generative AI.
Diamond Reflections

The Extraordinary Backstory of Natural Diamonds: A Diamond Is (and Has Been) Forever

Examines new developments in the story of diamond formation and their extraction from the earth.
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Figure 1. Blue sapphires from the Matepwende area in southern Tanzania. Most of the production consists of low-clarity material in matrix. Only a very small percentage (usually weighing less than 1 ct) is clean enough to be faceted. Photo by Vincent Pardieu.
Gem News International

New Production of Sapphire from Matepwende, Tanzania

Reports on the study of sapphire samples from a newly discovered source in southern Tanzania.
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Figure 2. This gold and emerald pendant contains 61 Colombian emeralds with 33 stones missing, presumably lost during its residence on the seafloor for more than 300 years. The pendant is approximately 3.5 in. (8.9 cm) wide. Photo by Emily Lane.
In the Spotlight

Splendors from the Deep: Historic Treasures from a Spanish Shipwreck

An in-depth look at jewelry recently recovered from a 1715 Spanish shipwreck.
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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