Thai ruby (3.66 cts) and Sri Lankan sapphire (2.75 cts). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Corundum | Blue

Corundum id-m-531125 - International Gem Society

Home

Gem Gallery

Join 10,000+ members helping each other learn. For gemologists, gem collectors, hobbyists, jewelers, lapidaries and everyone in between.

International Gem Society

https://www.gemsociety.org/wp-content/uploads/2015/06/igs_newsletter_logo.png

International Gem Society LLC

Corundum

Thai <a href="https://www.gemsociety.org/article/ruby-jewelry-and-gemstone-information/" data-wpel-link="internal">ruby</a> (3.66 cts) and Sri Lankan <a href="https://www.gemsociety.org/article/sapphire-jewelry-and-gemstone-information/" data-wpel-link="internal">sapphire</a> (2.75 cts). Photo © <a href="https://www.joelarem.com" data-wpel-link="external" target="_blank" rel="external nofollow">Joel E. Arem</a>, PhD, FGA. Used with permission.

A Guide to Gem Classification

Appraisals

Gem Cutting

Gemological Laboratories

Gemstones

Rough Gems and Mineral Specimens

Jewelry

Gemology Supplies and Equipment

Auctions

Gem Treating

Informational Resources

Lapidary Supplies and Equipment

Special Services

Ruby Buying Guide

Emerald Buying Guide

Sapphire Buying Guide

Aquamarine Buying Guide

An Introduction to Gem Identification

Destructive Gemstone Testing

Enhanced Gem Inclusions

Identifying Synthetic Diamonds

Insights on Gemstone Pricing

Polariscope Guide, Part 3: Testing for Gemstone Twinning, Dichroism, and Crystal Strain

Scheelite Value, Price, and Jewelry Information

The World’s Largest Emeralds

Swat Emerald

300-ct Citrine

What is this Green Gem Material?

Inherited Gemstones

Free Professional Business ListingGet your company in front of 12,000 gem enthusiasts and professionals.

Gemstone Buying GuidesAdvice that you can trust written by industry experts, without the giant price tag.

Professional Certification ProgramsOnly IGS Professional members are eligible to enroll in Professional Certification Programs

Advanced Filters in our Gem GalleryFilter images based on Gem State, Shape, Color, and Natural or Lab-Made

Gem Identification GuidesBe confident in what you have and avoid the heartbreak and cost of identification mistakes.

50% off all Mini CoursesOver $300 in savings

In-Depth Premium ArticlesIncluding 20 years of back catalog

Gem Price Guide (accurate and up-to-date)Reliable pricing data can cost hundreds through other sources. It’s included with IGS.

Gem Enthusiast

Gem Enthusiast Annual

Gem Enthusiast Monthly

For Professionals and Dedicated Enthusiasts

Professional Certification ProgramsOnly IGS Professional members are eligible to enroll in Professional Certification Programs (additional $400 per certification course)

More Advanced Filters in our Gem GalleryFilter images based on all of the basic filters PLUS Transparency, Multi-Color, Pleochroism, Phenomena, Treatment, and Inclusions

Access to All Mini Courses$600 value included in your membership

Professional

Professional Annual

Professional Monthly

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.

Gemstone	Corundum
Natural or man made	Natural
Gem State	Faceted
Color	RedBlue,
Transparency	Transparent