December Birthstones: Turquoise, Tanzanite and Zircon

Beautiful Winter Blues: Turquoise, Tanzanite & Zircon

December Birthstones

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Brilliance for the Next Generation

New Gemology Enrichment Programs
for Elementary Students

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FA23 G&G Issue Cover

Color in Yellow Sapphire, plus Oregon Sunstone and Canadian Iolite

New Gems & Gemology Issue

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featured

Research & News

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.
Feature

Color in Yellow Sapphire

Investigates the various chromophores responsible for color in four types of yellow sapphire.
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Knowledge Session Webinars
Webinar Series

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. The 4.04 ct ring fashioned from a single-crystal CVD-grown diamond. Photo by Towfiq Ahmed.
Lab Notes

Solid Laboratory-Grown Single-Crystal Diamond Ring

The quality and size of this 4.04 ct CVD-grown diamond ring demonstrate the advancing technology in laboratory-grown diamonds.
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Bladed crystals of columbite radiate from a central point in colorless topaz. The mirror-like surfaces allow for reflections of neighboring blades, as seen in the top left crystal. Photomicrograph by Tyler Smith; field of view 2.90 mm.
Micro-World

Spray of Columbite Crystals in Topaz

A cluster of bladed columbite crystals is identified in colorless topaz.
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Figure 1. Mineral inclusions in diamond. This connected pair of green clinopyroxene and orange garnet indicates that diamond growth occurred within an eclogitic mantle host rock. Photomicrograph by Nathan Renfro; field of view 2 mm.
Diamond Reflections

Eclogite: Diamond-Encrusted Ancient Seafloor

Explores eclogitic diamonds, which make up a significant portion of the gem diamond market, and what they reveal about Earth’s dynamic processes.
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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.
Gem News International

The Special Color Effect in “Chameleon” Amber

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