Table of Gems Ordered by Crystal System
This table contains a selection of minerals gemologists may encounter as jewelry stones or gem specimens. The gems are sorted by their crystal…
Specific Gravity Values of Selected Gems
Measuring specific gravity helps gemologists identify gemstones. The following table lists the specific gravity values for a variety of gem…
Table of Refractive Indices and Double Refraction of Selected Gems
Refractive indices and double refraction (birefringence) help gemologists identify gems. The following table lists these values for selected…
Pin Wheel: Online Faceting Designs and Diagrams
Inspired by the classic children’s toy, Jeff Graham’s award-winning Pin Wheel gem design is easy to cut and makes a very interesting stone.…
Phenomenal Gems – Unique Phenomena in Gemstones
Some optical effects in gemstones, such as color, brilliance, and dispersion, can be quite impressive. However, not all optical effects are considered…
The Art and Science of Identifying Gemstones
Trigon inclusions are part of a natural, uncut diamond’s original crystal structure. These were photographed on the surface of a rough…
Gemstone Magnetism: The Forgotten Property
Although gemstone magnetism isn’t a commonly tested gemstone property, it may be useful for making quick separations outside the lab. By Richard…
A Guide to Gem Classification
Step 1: Introduction to Gemology Lesson 6 Back to syllabus Little is simple and straightforward in gemology. Every established principle has…
Lapidary Fundamentals: Cabochon Cutting
Cabochon cutting or cabbing is the most popular form of gem cutting. Although it requires a fair amount of skill, almost anyone can master this technique.…
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