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SU25 GG Issue Cover

Phenomenal Gemstones, Gem Granitic Pegmatites, and Spotlight on Ben Kho

New Gems & Gemology Issue

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featured

Research & News

Tahitian Pearls
Retailer Resource

How GIA Analyzes Pearls from Start to Finish

Easy, step-by-step guide to how GIA analyzes pearls in its laboratory.
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Starry Night
Retailer Resource

How GIA Grades Colored Stones from Start to Finish

Easy, step-by-step guide to how GIA analyzes colored gemstones in its laboratory.
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Many loose laboratory-grown diamonds glowing under short-wave uv light
Retailer Resource

Testing Diamonds and Gems using UV Light

Quick how-to guide for retailers to test gemstone fluorescence and help identify stones in their own stores.
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Figure 6. This selection of deep-UV fluorescence images of natural diamonds highlights the wide range of potential emission patterns and colors that can be observed, evidence of diamond’s unique growth and residence history. E: Most natural type II diamonds show blue fluorescence with mosaic-like polygonized dislocation patterns, differing from characteristic type II CVD- or HPHT-grown diamond patterns (compare with figures 8–10). Images by Garrett Koneval (A), Najmeh Anjomani (B), Wuyi Wang (C), Christopher Vendrell (D), Ulrika F.S. D’Haenens-Johansson (E), and Sandeep Kabariya (F).
Glowing Gems - What Does Fluorescence Tell Us?

G&G in a Flash: What Does Fluorescence Tell Us?

Learn about the principles, mechanisms, and characteristics of luminescence that create the impressive and memorable glow of gemstones.
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CVD diamond plate and HPHT laboratory grown diamond
Laboratory-Grown Diamonds Update

The Latest on Laboratory-Grown Diamonds

Learn the latest trends by GIA on the laboratory-grown diamond industry.
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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. This 3.45 ct natural diamond was partially faceted to highlight the unusual clouds composed of dark micro-inclusions. Photomicrograph by Taryn Linzmeyer; field of view 7.19 mm.
Lab Notes

Unusual Patterns in Diamonds Composed of Dark Micro-Inclusions

Two natural diamonds exhibiting dark micro-inclusions are compared in the Carlsbad laboratory.
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Figure 2. The fibrous felted texture of the amphibole pebbles was revealed under magnification. Photomicrograph by Nathan Renfro; field of view 20.57 mm.
Micro-World

Mystery Pebbles in Quartz

Amphibole pebbles in quartz resemble rocks stacked in a stone wall.
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Figure 1. A selection of pegmatite gem crystals, including beryl, chrysoberyl, garnet, spodumene, topaz, and tourmaline. Photo by Mimi Travis; courtesy of the GIA Museum collection.
Colored Stones Unearthed

Gem Granitic Pegmatites

Describes the geology, mineralogy, and formation of granitic-composition pegmatites and provides a summary of their worldwide occurrences.
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Figure 1. Eight Kazakhstani emeralds (left) and three Ukrainian beryl and emerald samples (right), with gemological tweezers shown for scale. The leftmost Ukrainian emerald has a chemistry between that of aquamarine and emerald. Photo by Emily Lane; courtesy of Gerhard Franz and Oleksii Vyshnevskyi.
Gem News International

Emeralds and Beryl from Kazakhstan and Ukraine

A report from GIA’s Carlsbad laboratory on emerald and beryl samples studied as part of an ongoing beryl characterization research project.
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Figure 1. Ben Kho fashioned this 12.88 ct Portuguese cushion-cut rhodochrosite from Colorado’s Sweet Home mine to win both the 2024 AGTA Cutting Edge Buyer’s Choice Award and second place in the North American Gemstones category. Photo by Jeff Mason Photography; courtesy of Ben Kho.
In the Spotlight

Ben Kho: From Rough Beginnings to Brilliant Mastery

Profiles the extraordinary life and work of Ben Kho, from a young entrepreneur in Cambodia to an award-winning gem cutter.
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Figure 1. A variety of some of the most common phenomenal gemstones. Top row, left to right: 2.35 ct 12-rayed star sapphire from Sri Lanka, gift of Gordon Bleck, GIA Museum no. 17037; 18.18 ct blue star sapphire, courtesy of Evan Caplan; 18.29 ct star ruby from Myanmar, courtesy of the Natural History Museum of Los Angeles County; 36.76 ct cat’s-eye tourmaline from Brazil, courtesy of Pala International. Bottom row, left to right: 7.60 ct moonstone from Sri Lanka; 11.0 ct Oregon sunstone displaying aventurescence over red and green bodycolors; 11.45 ct black opal from Australia displaying vibrant play-of-color; 30.82 ct Finnish labradorite cabochon from GIA’s Dr. Edward J. Gübelin collection. Photos by Robert Weldon (six stones on the left) and Orasa Weldon (two stones on the right).
Feature

Review of Optical Effects in Phenomenal Gemstones

A comprehensive summary of the special optical effects in gemstones.
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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