Understanding Gem Synthetics, Treatments, and Imitations, Part 5: Gemstone Treatments
Identifying gemstone treatments is difficult even for experienced gemologists. Learn about the many different ways gem color and clarity are…
What Happened to the GIA GemSet Color and Hue Wheel?
The GIA GemSet offered plastic color masters for color grading gems. It’s no longer in production. Software alternatives exist but still face…
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…
Identifying Synthetic Diamonds
Although most manufacturers disclose their synthetic diamonds, some resellers don’t. Learn how to identify these lab-created diamonds.…
Gemology Cheat Sheets
These gemology cheat sheets review gem color and clarity grading, specific information on evaluating diamonds and opals, and basic gem identification…
Gemstone Visual Examination Quizzes
A visual examination is the first step to identifying a gemstone. These quizzes will help student gemologists learn to recognize what they might…
Gemstone Magnetism
Although gemstone magnetism isn’t a commonly tested gemstone property, it may be useful for making quick separations outside the lab. By Richard…
Measuring the Refractive Index of Cabochons
Step 3: Practical Gemology Lesson 5 Back to syllabus You can use a refractometer to determine the refractive indices (RI) of most cabochons and…
Optical Properties of Gemstones
We tend to take light for granted. It’s such a common thing we experience every day. Rarely do we think of the scientific definition of light…
IGS Become Member