Turquoise Value, Price, and Jewelry Information
Discover turquoise gemstone value factors, history, colors, treatments, and care. Learn how to identify genuine stones, top mining sources,…
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…
Sugilite Value, Price, and Jewelry Information
What is the color of sugilite? Grape jelly purple is a good description. More popular among consumers in Asia than North America, this is a very rare…
Gem Formation: How are Gemstones Created?
Most gems form naturally as minerals within the Earth. Most form as crystals, solids whose atoms are arranged in highly ordered repeating patterns…
The Physical Properties of Gemstones
Step 2: Advanced Gemology Lesson 2 Back to syllabus The optical properties of gems attract our eyes and can give a cut stone a unique character. However,…
Grading Gem Carvings
Gem carvings vary widely in size, shape, and quality. You can find small, simple carvings with a glued-on bail for just a couple of dollars. Fine…
Destructive Gemstone Tests: Acid Testing
In some cases, a hot point test won’t distinguish plastic simulants from natural gems. Some plastics release a protein smell when hot point…
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…
Destructive Gemstone Tests: Streak Testing
Gemstone streak testing is fun if you have rough material to spare. It’s not recommended for finished gems, as there’s a good chance…
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