Jade Sources

How to Measure an OTL Gemstone Refractive Index

Gem Origin Opinions: When Gemology Labs Agree to Disagree on Sapphire Origins

Emerald Origins: History and Identification

Aquamarine Sources

Gemstone Physical Properties

Gemstone Photomicrography: Photographing Inclusions

Gemstones and Refraction Liquids

Ouro Verde Quartz: History and Treatment

HPHT Diamond Treatments

Quartz Color Treatments

Identifying Garnets Simplified

Gemstone Radiation Treatment

Impurity Ions and Gemstone Colors

Emerald Fillers and Treatments

Identifying Inclusions of Specific Gems

Shells and Sea Shells

Fossilized Organisms

Advanced gemology topics on a wide variety of technical subjects such as gemstone treatments and inclusions.

Advanced Gemology Topics

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Ruby Buying Guide

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An Introduction to Gem Identification

Destructive Gemstone Testing

Enhanced Gem Inclusions

Identifying Synthetic Diamonds

Pricing Faceted Gems and Calculating Your Return

Gemology Book Reviews: Careers

Augelite Value, Price, and Jewelry Information

Six Famous Aquamarines

Recut Tourmaline

Mystery Mark on Ring

What is this Green Gemstone?

A Trichroic Gem

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Birthstone Chart

37 Blue Gemstones (Names, Pics, & More)

Gemstone Hardness and Wearability

10 Rare Engagement Ring Stones that Won’t Break the Bank

Gübelin Grades an Exceptional Vietnamese Ruby with “Pigeon’s Blood” Color

Distinguishing Common Jade Lookalikes

An Interview with “Diamond Wizard” Maarten de Witte: Part 4

Jade Color Trade Names

In 2012, Donald Clark retired and passed along stewardship of the IGS to the Rosen family, who were longtime members of IGS. Lisa Rosen runs the day-to-day operation of IGS and  <a href="https://www.ganoksin.com/">The Ganoksin Project, a technical resource website for bench jewelers and jewelry manufacturers</a>.  Lisa strongly believes that IGS must remain a cost-effective, accurate, and comprehensive resource for all those interested in gemology. IGS is our passion, and it is a family business.

Lisa Rosen

The late Donald Clark, CSM founded the International Gem Society in 1998. Donald started in the gem and jewelry industry in 1976. He received his formal gemology training from the Gemological Institute of America (GIA) and the American Society of Gemcutters (ASG). The letters &#8220;CSM&#8221; after his name stood for Certified Supreme Master Gemcutter, a designation of Wykoff&#8217;s ASG which has often been referred to as the doctorate of gem cutting. The American Society of Gemcutters only had 54 people reach this level. Along with dozens of articles for leading trade magazines, Donald authored the book &#8220;Modern Faceting, the Easy Way.&#8221;

Donald Clark, CSM IMG

Jeffery Bergman, SSEF SGC, founder and director of <a href="http://www.primagem.com/">8th Dimension Gems</a> in Thailand, is an American gem dealer with more than 40 years of experience in gemstone and fine jewelry mining, cutting, wholesaling and retailing. His career has taken him to more than 50 countries and every continent except Antarctica. He has appeared on the BBC, CNN, NBC, ABC and GEO; and has been featured in Time, USA Today, National Geographic, Gems &amp; Gemology and Discovery Channel magazine. He is a regular guest speaker at gem lab seminars and gemological association conferences and universities.

Jeffery Bergman, SSEF SGC

Dr. Joel E. Arem has more than 60 years of experience in the world of gems and minerals. After obtaining his Ph.D. in Mineralogy from Harvard University, he has published numerous books that are still among the most widely used references and guidebooks on crystals, gems and minerals in the world.
Co-founder and President of numerous organizations, Dr. Arem has enjoyed a lifelong career in mineralogy and gemology. He has been a Smithsonian scientist and Curator, a consultant to many well-known companies and institutions, and a prolific author and speaker. Although his main activities have been as a gem cutter and dealer, his focus has always been education. <a href="https://www.joelarem.com/">joelarem.com</a>

Joel E. Arem, Ph.D., FGA

Fatma Oya Borahan, GG, FGG has Graduate Gemologist and Diamond Diplomas from the Gemological Institute of America (GIA) the German Gemmological Association (DGemG) and Gemmological Association of Great Britain (GemA). <a href="http://birdamlasu.com/">birdamlasu.com</a>

Fatma Oya Borahan, GG, FGG

Barbara Smigel is a GIA certified gemologist, facetor, jewelry designer, gem dealer, gemology instructor and creator of the well-regarded educational websites <a href="http://www.acstones.com">acstones.com</a> and <a href="http://www.bwsmigel.info">bwsmigel.info</a>.

Barbara Smigel, PhD. GG

Dr. Gerald Wykoff is GG (Graduate Gemologist), a CSM (Certified Supreme Master gemcutter), educator, and author of several gemology books. He founded the American Society of Gemcutters in the 1980s and served for more than 10 years as the editor of its monthly magazine, American Gemcutter.

Dr. Gerald Wykoff GG CSM

A geologist, environmental engineer and Caltech graduate, Addison&#8217;s interest in the mesmerizing and beautiful results of earth&#8217;s geological processes began in her elementary school&#8217;s environmental club. When she isn&#8217;t writing about gems and minerals, Addison spends winters studying ancient climates in Iceland and summers hiking the Colorado Rockies.

Addison Rice

The late Jeff Graham was a prolific faceter, creator of many original faceting designs, and the author of several highly-regarded instructional faceting books such as <a href="https://rockpeddler.com/product-category/instructional-materials/">Gram Faceting Designs</a>.

Jeff R. Graham

Bear Williams, CG, FGA (Hon), is President and Laboratory Director at <a href="https://stonegrouplabs.com/">Stone Group Laboratories</a>. Bear travels to gem producing countries and treating regions researching the latest trends in gemology and visiting with other lab directors. On-site research allows him to keep abreast of new synthetics and treatments in the marketplace. He regularly meets with other gemological associations and labs, and together will present research findings, and discuss the latest nomenclature or laboratory issues relevant to the trade and consumers. Recognized as an expert in the field of digital spectroscopy, Bear operates UV-Vis-NIR, ED-XRF, FTIR, UV, and Raman Spectrometers.

Bear Williams

Cara Williams, FGA, is Vice-President and Senior Staff Gemologist at <a href="https://stonegrouplabs.com/">Stone Group Laboratories</a>. Cara is a fellow of the Gemmological Association of Great Britain (Gem-A). She has been a tutor for the prestigious Diploma in Gemmology course for the Gem-A in London for more than 15 years. Growing up in a retail jewelry family with a concentration in colored stones, Cara has been in the wholesale trade since 1986. She brings a lifetime of experience working with gems to the lab, her students, and many published articles.

Cara Williams

Kyrylo Gubariev, Graduate Gemologist (GG, AJP) is a gemologist with a passion for sharing his knowledge with fellow gem lovers. Originally from Ukraine, he is currently based in Bangkok, Thailand.

Kyrylo Gubariev, Graduate Gemologist (GG, AJP)

Advanced Gemology Topics - International Gem Society

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