The very rare multiple star-effect in this cabbed quartz are caused by inclusions of sillimanite. 15.68 cts, 14.3 x 14.4mm, Sri Lanka. © The Gem Trader. Used with permission.

Quartz | Colorless | 15.68 ct

Quartz id-m-517030 - International Gem Society

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Quartz

The very rare multiple star-effect in this cabbed <a href="https://www.gemsociety.org/article/quartz-jewelry-and-gemstone-information/" data-wpel-link="internal">quartz</a> are caused by inclusions of sillimanite. 15.68 cts, 14.3 x 14.4mm, Sri Lanka. © The Gem Trader. Used with permission.

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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.

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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

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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.
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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.

Gemstone	Quartz
Natural or man made	Natural
Origin	Sri Lanka
Carat Weight	15.68
Height	14.3
Width	14.4
Gem State	Cabochon
Color	Colorless
Transparency	Translucent
Photo phenomena	Asterism