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 "CSM" after his name stood for Certified Supreme Master Gemcutter, a designation of Wykoff'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 Modern Faceting, the Easy Way.

Jeffery Bergman was a contributor to IGS long before its current ownership.  Aside from Don Clark, he is the longest-standing contributor to IGS.  In honor of his decade of friendship and support, Jeffery holds the honorary title of Vice President, Emeritus – International Gem Society.  He is, and always has been, a fully pro-bono contributor and maintains no financial interest in IGS.

With humble roots from a non-gem trade family, as a lapidary hobbyist, Jeffery cut and polished his first gemstone at the age of fourteen launching him on a lifelong career which has taken him to more than 70 countries, and every continent except Antarctica. With 5 decades of broad-based experience in natural gemstones, diamonds and fine jewelry, in 2020 Jeffery founded Eighth Dimension Gems (formerly Primagem) in Bangkok, Thailand, where he has lived for over 30 years.

Jeffery’s formal gemmological training was accomplished at the prestigious Swiss Gemmological Institute in Basel, Switzerland where he passed requisite exams for his SSEF Basic Gemmology (BGC) and SSEF Basic Diamonds (BDC) Diplomas. Additionally, he completed SSEF's Advanced Pearls (ATC), Advanced Colored Stones (ATC) and Scientific Gemmology (SGC) courses, and is privileged to be an active SSEF BGC & BDC Accredited Senior Gemologist voting member of the AGA – Accredited Gemologists Association.

Featured in many gem and jewelry periodicals, Jeffery has also appeared in interviews on the ABC, BBC, CCTV, CNA, CNN, NBC and GEO. He has been quoted in Time, USA Today, National Geographic, Discover, GIA’s Gems & Gemology, Gem-A’s Journal of Gemmology, ICA’s InColor, Rivista Italiana di Gemmologia/Italian Gemological Review and many other publications around the world. A guest speaker at seven GIA Gem Gatherings as well as many gemological conferences & universities, Jeffery is also an Honorary Professor for the AIGS - Asian Institute of Gemological Sciences in Bangkok, Thailand.

Dr. Joel E. Arem, PhD, FGA, 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. JoelArem.com

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). birdamlasu.com

Barbara Smigel PhD, GG, is a GIA certified gemologist, facetor, jewelry designer, gem dealer, gemology instructor, and creator of the well-regarded educational websites acstones.com and bwsmigel.info.

A geologist, environmental engineer and Caltech graduate, Addison's interest in the mesmerizing and beautiful results of earth's geological processes began in her elementary school's environmental club. When she isn't writing about gems and minerals, Addison spends winters studying ancient climates in Iceland and summers hiking the Colorado Rockies.

Dr. Gerald Wykoff was a 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.

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 Gram Faceting Designs.

Bear Williams, CG, FGA (Hon), is President and Laboratory Director at Stone Group Laboratories. 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.

Cara Williams, FGA, is Vice-President and Senior Staff Gemologist at Stone Group Laboratories. 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.

Megan Coward GG, GJG, is a graduate of the GIA with Graduate Jeweler Gemologist and Graduate Gemologist accreditations. She has 20+ years in the retail jewelry industry in various roles including as a diamond buyer and gemstone appraiser.

A gem lover and writer, Phoebe Shang, GG, holds a graduate gemologist degree from the Gemological Institute of America and masters in writing from Columbia University. She got her start in gemology translating and editing Colored Stone and Mineral Highlights for a professor based in Shanghai. Whether in LA, Taipei, or New York, Phoebe spends her time searching for gems to design and being lost in good books.

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.