About

Don 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."

Articles by


Don Clark

Tips for Cabbing and Carving Opals

Opal cabochons can fetch high prices but may be difficult to cut. These tips for carving opals can help gem cutters make the most of these beautiful…

Grading Gem Carvings

Gem carvings are judged on material, workmanship, and artistry. Learn how to apply these criteria to a piece with our step-by-step guide.

An Introduction to Gemology

Learn what gemologists do in our introduction to gemology. Whether your interest is casual or professional, the world of gems will amaze you.

How to Grade Fancy Cut Diamonds

Fancy cut diamonds can have any finished shape, except round. These stones have their own grading criteria, in particular regarding proportion…

How to Grade Set Gemstones

Gems in jewelry settings can’t be evaluated the same way as loose stones. These guidelines are for gemologists learning to grade set gemstones.…

Top Spots for Gem Hunting in the US

Visit one of the top gem hunting spots in the US. Go alone or with the family. A gemology-themed vacation can be fun, educational, and (maybe) profitable.…

A Guide to Gem Cutting Styles

Gem cutting styles refer to the shape and arrangement of facets. The three most basic styles are brilliant, step, and mixed. Learn what characterizes…

Gemology Cheat Sheets

These gemology cheat sheets review gem color and clarity grading, specific information on evaluating diamonds and opals, and basic gem identification…

Modern Diamond Cut Grading Methods

The GIA modern diamond cut grading method is the most widely accepted in the industry. Our step-by-step guide covers the tools and techniques you’ll…

Clarity Grading Diamonds

Mastering clarity grading diamonds takes a lot of experience. This grading guide, with definitions, images, and examples, can help beginning…

Color Grading White Diamonds

Mastering the art of color grading white diamonds is a challenge. Learn about the standards, terms, tools, and testing procedures and start practicing.…

Choosing Faceting Angles

With so many recommended faceting angles, new gem cutters can have a hard time choosing. Learn the basic guidelines and some exceptions to the rules.…

Identifying Synthetic Diamonds

Although making gem-quality synthetic diamonds still costs more than mining natural stones, some lab methods can yield gem-grade materials.…

Identifying Synthetic Gems

Distinguishing between natural and synthetic gems is a critical skill for gemologists. Learn about gem making processes and the telltale signs…

A View of The Quartzsite Gem Shows

The Quartzsite gem shows attract gemologists and rock hounds from around the world. Learn what to expect and how to shop at these huge annual January…

Gemstone Optical Properties

Rarely do we think of the scientific definition of light or its properties. However, light plays a critical role in gemology. You must first understand…

Gemstone Physical Properties

The optical properties of gems attract our eyes and can give a cut stone a unique character. However, gemstone physical properties are also important.…

The Spectroscope in Gemology

The spectroscope is a fundamental gemological tool. Learn how to use it to identify gemstones based on their absorption of different wavelengths…

Appraising Gems and Jewelry

Appraising gems and jewelry involves opinions of value based on knowledge and research. Learn what information gemologists should include on…

How To Correct Faceting Mistakes

We faceters all like to take pride in our work. However, no matter our skill level, we all make errors. However, you can learn a few tricks for correcting…

Gemstone Color Change Phenomena

Frequently, people ask me to explain how gemstone color change works. Some stones can change color under different light sources. Although the…

Gem Pricing Advice for Faceters

Novice gem cutters often ask me about gem pricing. They want to know how to determine a fair price for what they cut. This is never an easy question.…

Custom Gem Faceting Styles

Gem cutters can choose from many faceting styles. Learn about the most common custom cutting techniques and pick one that suits your needs and skill…

An Introduction to Gemstone Grading

There were no standards for grading gems ’til the 30’s. Then the G.I.A. instituted the Four C’s method for diamonds, which has now become the standard.…

What is a Gem?

Even the most general definition of a gem has many exceptions. Learn what qualities have been used to identify gemstones both scientifically and…

Combining Stones in Jewelry

Combining stones can be more than adding diamond accents to colored gemstone jewelry. Explore colored stone combos and learn how to set gems within…

A Guide to Gem Classification

There is not one way to classify gems, rather there are several ways, each of which has its own purpose and its own exceptions that warrant close attention.…

What are Gemstone Enhancements?

Gemstone enhancements improve the appearance and wearability of gems. Learn about the most commonly used procedures and frequently treated…

Jewelry Nomenclature: Gem Settings

Jewelry designers and consumers can pick from many different gem settings. Learn the names and uses of common and speciality settings for any type…

Tips for Cutting Kunzite

Cutting kunzite and other gemstones with easy cleavage is challenging. These tips can help you facet this beautiful and valuable gem.

Cutting Star and Cat’s Eye Gems

Learn how to cut star and cat’s eye gems. Once you understand how these light effects work, you’ll find unexpected treasures in overlooked gemstone…

Gemstone Dopping Techniques

A novice gem cutter needs to master various dopping techniques for cabbing and faceting gemstones. Learn how to attach gem rough to a dop stick safely.…

The Gemstone Butterfly Cut

The Butterfly Cut is a stunning design for a custom gem. Our diagrams and guide can help faceters and consumers plan the perfect cut for any jewelry…

Angles for Cutting Garnets

Cutting garnets and other color saturated gems for brilliance can be challenging. Here’s some advice for choosing the best angles for color and…

Identifying Garnets Simplified

Identifying garnets by species is complicated. Learn how to use refractive index, hue, and absorption spectrum readings to simply the separation…

Gemstone Examination Lesson

Learning how to conduct a gemstone examination takes practice. Follow an expert gemologist step-by-step through tests of five unknown samples.…

Difficult Gemstone Separations

Two of the trickiest gemstone separations to make are scapolite from citrine and apatite from tourmaline. Learn some tips for distinguishing…

Carats and Gemstone Grading

Carats are the units used to measure gem weight and one of the main factors in gem grading. Learn what affects the value per carat of various gem species.…

Appraising Opals

Opals are unique gems with their own unique terminology. Learn the modern standard system for classifying and appraising opals used by major gem…

Opal Buying Guide

Our opal buying guide can help you learn how opals are graded, what to avoid, and how to identify a high quality stone or a bargain in the rough.

Australian Opals

Australian opals account for 95% of the world’s supply. Learn about Australia’s geological history, the start of its opal trade, and its sources.…

Product Review, Opal Smart Chart

The newest thing in the opal world is the Opal Smart Chart. This is a software package designed to help you value your opals. It has two segments.

Product Comparison, Polariscopes

Polariscopes are one of our most useful instruments. They come in a wide variety of prices and qualities. There are a number of ways to make a polariscope.…

Product Review, Sony Cyber-shot

A Product Review on Sony Cyber-shot. Overall, it is an excellent camera and I was surprised by the low cost.The image quality is excellent at any…

Product Review, Diamond Calculator

There is a new piece of software available that will be of interest to many of you. It is called the Diamond Calculator. More information available…

Destructive Gemstone Testing

Destructive gemstone testing, done carefully, can help gemologists with difficult gem identifications. Learn the right techniques with our…

The Dichroscope

The dichroscope is one of the most useful instruments a gemologist can have. Its primary purpose is to determine the pleochroism of a gem.

Living With Your Faceting Machine

One serious pitfall for the novice is the quality of advice they get in choosing what faceting machine to buy. Here are a few tips in choosing the right…

Inclusion Management

Inclusion management is one of the last elements of faceting to be learned and also the most difficult aspects of faceting. Some faceters never…

Polishing Laps and Techniques

Polishing Laps and Techniques. Covers helpful information, tips, suggestions for polishing. A guide on techniques that will be useful for polishing…

Faceting Machine Survey

Recently, a survey was taken to see what kind of Facet Machines are being used by members of the Faceter’s Digest . 246 people had responded to the…

Soldering Precious Metals

Soldering is one of the most useful techniques a metal smith can have. It is used both to create new pieces and to repair damaged jewelry.

Corundum Treatments

Many techniques have been developed to enhance the appearance of Corundum gems. Some of the treatments are very subtle, invisible even with a loupe.…

Sea Shells

Sea shells are one of our most ancient decorations. Their earliest use was to string them into a necklace, or hang them from a cord as pendants.

HPHT Diamond Update

Gemologists are seeing more and more HPHT diamonds. While detection equipment is costly, you can assess the likelihood of treatment without it.…

How to Make a Beaded Necklace

An overview on How to Make a Beaded Necklace. Detailed information on the tools, materials, designs and techniques on making a beautiful beaded…

How Rare Is That Gem?

Rarity is one of the most prized qualities of gemstones. But some gems are far more rare than others! This article helps explain what’s rare and what…