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Gemstone buying guides

Whether you’re a gem enthusiast or work with gems professionally, the IGS buying guides are the cornerstone to building confidence in working with gems. Enjoy over 46 gemstone-specific buying guides ranging from sapphires and emeralds to more exotic gems like quahog pearls and chrysoprase. These unique resources extensively cover all of the gemological basics, the properties of each gem, special information, considerations for jewelers, treatments to consider, factors that influence gem pricing, and much more.

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By Phoebe Shang, GG

It doesn't matter how much you think you know about gems, you never stop learning

You know the best thing that I've learned from your great course is that it doesn't matter how much you think you know about gems, you never stop learning. Each day there is something more to learn, and it will never stop. Thank you for all the help, education and support that you give IGS members.
Peter Checkley IGS Pro Member

What started as a hobby is now a small home business for my wife and I

I have never known or heard of an organization that offers so much for its members, and at such a low cost. What started as a hobby in 1998 and now is a small home business for my wife and I has been made so much easier by the information you supply. Thank you.
Ernest Roisch Rainbow Rocks, LTD

What a gift you give, passing this knowledge to those of us who are seekers

Just wanted to thank you for the fantastic adventure I have had since becoming a member of IGS. The quality of your Gemology Course is tops. Nice to know that such folks as you exist. What a gift you give, passing this knowledge along to those of us who are seekers.
Dr. John Parrott IGS Member
Enhanced Gem Inclusions

Identification & grading guides

Gemstone identification is a fundamental skill for enthusiasts and professionals alike. Learn the art and science of identifying gemstones with identification guides created by industry experts. You’ll learn...

  • How to use the same tests used by industry professionals
  • The latest ways to spot synthetics, imitations, and treatments.
  • Avanced identification techniques, tips on difficult gemstone separations, and destructive tests.
  • How to avoid poor and dated information from unverified sources, random internet sites, and common wisdom that can lead to heartache and costly mistakes.

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Industry news & developments

By joining IGS, you gain access to reputable and comprehensive information on the latest changes and evolutions in the gemstone market such as:

Gem treatments

Stay on top of the latest gem treatments being used to fool buyers (IGS has your back in this constant game of cat and mouse).

Simulants & synthetics

IGS keeps you updated on all the latest in lab grown material, assembled stones, methods, approaches, and more.

New gemstone finds

Be one of the first to hear about often-undervalued new gem deposit discoveries and their influence on supply.

New gem cuts

Enjoy extensive coverage of the ever-changing lapidary landscape, and consumer demand for well-cut colored gems.

Accurate gem pricing data

Enjoy unlimited access to up-to-date prices and quality guidance on over 70 types of gemstones, all at the click of a button.

  • Prices are compiled and updated by gem dealers and gemology professionals that understand the gem market.
  • At-a-glance info tells you what to look for in a gemstone, how its properties affect its value, and how to spot a deal.
  • Stay up-to-date on the latest approaches that labs use for identifying, certifying, and grading stones.

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Ruby Value
0.50-0.99 CTS $10,000 - $18,000/CT
1.00-1.99 CTS $20,000 - $35,000/CT
2.00-2.99 CTS $50,000 - $70,000/CT

270+ exclusive premium articles

For the last 23 years, IGS has researched, developed, and refined the very best gemology content on the Internet written by the most respected gemologists, stone cutters, and dealers in the trade. New articles including difficult-to-find information are researched and published every week!

The Microscope: A Guide for Gemologists
The Microscope: A Guide for Gemologists
Read more
Destructive Gemstone Tests: Acid Testing
Destructive Gemstone Tests: Acid Testing
Read more
Aquamarine Specialist Mini Course
Progress 75%
Beginner 3 Units 13 Lessons

VIP access to IGS mini courses

Take your gem education to the next level with structured mini courses from IGS. Gem Enthusiast members receive mini courses for 50% off, and Professional members receive them free! Mini-courses include...

  • Jade Specialist
  • Lab Grown Diamonds Fundamentals
  • Diamond Fundamentals
  • Aquamarine Specialist
  • Tourmaline Specialist
  • Gemology Tools
  • Topaz Specialist
  • Garnet Specialist
  • Citrine Specialist
  • Buying Gems for Profit
  • Emerald Specialist
  • Sapphire Specialist
  • Ruby Specialist
  • Pearl Specialist
  • Opal Specialist

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2 exclusive pro-level certifications

Professional members are eligible for two exclusive certification courses designed to provide flexible and affordable options for continued education. Each course requires a $400 enrollment fee.

Professional Gemologist Certification Course
95 lessons with robust testing designed to help you stand out from the crowd with a recognized, valuable certification.

Diamond Specialist Certification Course
50 lessons on the fundamentals of diamonds — from optical and physical properties to grading and ethical and legal issues.

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Professional Gemologist Certification Course
Progress 60%
Intermediate 6 Units 95 Lessons

Members-only IGS forum access

Have a unique gem you can’t identify? Questions on equipment? Gemstone pricing? Connect with gemstone professionals and enthusiasts around the world to get help and share your own knowledge.

120-day money back guarantee

Take 4 Months to Decide if IGS is Right For You

We believe that joining IGS will save you time, money and heartache on your gemstone education and purchases. Our community of fellow enthusiasts and professionals wholeheartedly agree, which is why we are able to confidently extend a full 120-day money back guarantee on your membership. If you decide that IGS isn’t right for you for any reason, we’ll refund your membership purchase within 120 days of purchase; or your course purchase within 14 days of purchase. No questions asked.

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Still have questions?

Can’t I just learn this information from books?

You can learn a lot about gemology from books. But you would need quite a large and expensive library!

Here are a few things to consider. For starters, books rapidly become dated. Our materials are constantly updated with the latest new finds, market prices, and trends in the gemstone world.

You just can’t cover this effectively in a published book format. Beyond that, books are not interactive. Inside of IGS, you’ll get access to exclusive imagery, video content, and quizzes to help you test your knowledge.

Not to mention, you can tap into our community of experts and fellow gem professionals inside of our forums.

If I care about working with gemstones professionally, shouldn’t I take in-person classes?

It depends on how you learn most effectively. In-person classes are costly, time-consuming, and might even involve travel.

Our mission at IGS is to provide a cost-effective and efficient alternative to in-person learning.

Ultimately, if you intend to work with gems professionally you’ll need hands-on experience. This demands that you make a commitment to study, work with gems, and learn from your mistakes along the way.

Like everything else, it takes time to develop confidence and mastery with gemstones.

Is this just memorizing facts? Or will I gain practical knowledge and skills?

Memorization is not something we ever advocate. That’s why IGS provides resources that you can access around the clock — so you can learn on your own schedule!

We’re by your side throughout your gemology journey. Not only do we teach you how to use advanced techniques and run your own tests, but practical knowledge and skills are also packed into every piece of content.

You get access to all of it with your membership. However, what you need to bring is motivation! If you’re driven to learn and practice your skills, we guarantee that you’ll get value from your membership.

How is IGS different from free gemstone content online?

We’re glad you asked! There’s no shortage of gemstone information available online. Some of it is good, and quite frankly, a lot of it isn’t.

Anyone can publish anything on the internet — and they often do. The reality is, gemology is science. Writing about a scientific topic with intellectual rigor and accuracy requires time, money, and commitment.

We invest in our content and we care about our reputation. Our writers, contributors, and editors spend a lot of time to make sure that the content you are relying upon is high quality, research-driven, and heavily scrutinized for accuracy.

Given that our membership costs about the same as a few cups of coffee per month, we think it’s an incredible value.

What if I join and decide this isn’t right for me?

We stand by our guarantee. You have a full 120 days to experience the membership and decide if it’s right for you. If you’re not completely satisfied, we’ll refund your membership within 120 days of purchase—or your course purchase within 14 days of purchase.

Plus, if you decide to join our month-to-month plan, you can cancel at any time and you won’t be billed for the next month.

Start your membership today

and join 20,693 gem enthusiasts and professionals around the world

Professional Enthusiast

Gem Enthusiast Membership

For Hobbyists and Enthusiasts

  • Gemstone Buying GuidesAdvice that you can trust written by industry experts, without the giant price tag.
  • Gem Identification GuidesBe confident in what you have and avoid the heartbreak and cost of identification mistakes.
  • Gem Price Guide (accurate and up-to-date)Reliable pricing data can cost hundreds through other sources. It’s included with IGS.
  • In-Depth Premium ArticlesIncluding 20 years of back catalog
  • Complete Forum Access
  • 50% off all Mini CoursesOver $300 in savings
  • Professional Certification ProgramsOnly IGS Professional members are eligible to enroll in Professional Certification Programs
  • Free Professional Business ListingGet your company in front of 12,000 gem enthusiasts and professionals.
$12 /mo
$97 Save 30% /yr
Start your membership 120-day money-back guarantee

Becoming a Pro Member of IGS just made good sense for my business.

The gemology resources are fantastic, and my profile lets potential customers know I am serious about colored gemstones. And frankly, if I get any exposure to potential customers it's a no-brainer.
Paul Bierker Paul Michael Designs

Unparalleled expertise

our founder, contributors, and technical advisors

Donald Clark


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.

Jeffrey Bergman

Vice President Emeritus

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. 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 Arem


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.

Fatma Oya Borahan


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).

Barbara Smigel


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

Addison Rice

Staff Writer

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.

Gerald Wykoff


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.

Jeff Graham


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


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


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

Staff Writer

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.

Phoebe Shang

Staff Writer

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


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.