Advanced Gemology Topics
Advanced gemology topics on a wide variety of technical subjects such as gemstone treatments and inclusions.
Spinel Sources
Learn about important spinel sources across the globe — from historical mines to recent discoveries — and the colors they...
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Jade Sources
Jadeite and nephrite occur all over the world. Learn about the most notable and productive gem-quality jade sources..
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How to Measure an OTL Gemstone Refractive Index
Measuring “over the limit” (OTL) refractive indices can help distinguish diamonds from simulants. You can do this with a simple...
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Gem Origin Opinions: When Gemology Labs Agree to Disagree on Sapphire Origins
Why do gemology labs sometimes have different gem origin opinions, especially for sapphires? Learn the science and history behind the...
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Emerald Origins: History and Identification
Emeralds from different sources can vary in quality. Learn how to identify emerald origins by analyzing the optical and physical...
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Aquamarine Sources
Aquamarines are popular gemstones and can be found in many areas worldwide. Learn about some prized varieties and the most...
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Gemstone Physical Properties
The optical properties of gems attract our eyes and can give a cut stone a unique character. However, gemstone physical...
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Gemstone Photomicrography: Photographing Inclusions
Explore the amazing world of gemstone photomicrography. These tips can help you view and photograph spectacular inclusions found inside many...
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Gemstones and Refraction Liquids
Gemologists use refraction liquids to identify gemstone refractive indices (RI). Learn about the properties of these liquids and safe RI...
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Ouro Verde Quartz: History and Treatment
Ouro Verde quartz, also known as lemon quartz, is a popular treated stone. Learn how experiments with other gems led...
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HPHT Diamond Treatments
HPHT diamond treatments can only be positively identified with costly equipment. However, you can learn to assess the probability that...
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Quartz Color Treatments
Quartz color treatment results vary due to the stone's origin. Learn the effects you can achieve with different materials and...
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Identifying Garnets Simplified
Identifying garnets by species is complicated. Learn how to use refractive index, hue, and absorption spectrum readings to simply the...
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Gemstone Radiation Treatment
Gemstone radiation is a common but little understood technique for altering gem colors. Learn how it works and what gems...
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Impurity Ions and Gemstone Colors
How do gems likes rubies and red beryls get their red color? Learn the role impurity ions play in the...
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Emerald Fillers and Treatments
Emerald fillers can improve the beauty of these gems but also have some drawbacks. Learn how to choose the right...
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Identifying Inclusions of Specific Gems
Some natural as well as synthetic gems have specific, characteristic inclusions. Learn the identifying inclusions of some of the most...
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Shells and Sea Shells
Sea shells are one of our most ancient decorations. Our prehistoric ancestors used to string them into necklaces or hang...
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Fossilized Organisms
Most people who have an interest in gemstones or nature have seen petrified wood, but fewer are aware of the...
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