Physical and Optical Properties of Gemstones
Learn about gemstone color, crystallography, hardness, chemical makeup and more.
Gemstone Color Measurements and Specifications
Gemstone color measurements are hard to make with conventional color-order systems. Learn how recent colorimetry tech advances have improved accuracy....
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Gemstone Color Change Phenomena
Why do certain gems change color under different lights? Explore gemstone color change phenomena and the difference between natural and...
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What are Allochromatic and Idiochromatic Gems?
Learn the difference between allochromatic and idiochromatic gems and why some gem species can occur in many color varieties and...
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Phenomenal Gems: Cat’s Eyes, Star Stones, and More
Phenomenal gems seem to do magical things with light. Learn the science behind optical effects like cat’s eyes and star...
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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 Optical Properties
Learn how gemstone optical properties, like refractive index and pleochroism, help gemologists identify gems and lapidaries choose cuts.
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What are Gemstone Enhancements?
Gemstone enhancements improve the appearance and wearability of gems. Learn about the most commonly used procedures and frequently treated types...
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Gemstone Thermal Properties
Non-destructive tests are critical for gemologists trying to identify gems. Learn how measuring thermal properties, especially thermal inertia, can help....
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What is Gemstone Pleochroism?
Some gems show pleochroism, two or three different colors depending on the viewing angle. Learn why this occurs and how...
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Gemstone Magnetism: The Forgotten Property
Although gemstone magnetism isn't commonly tested, it can help gemologists distinguish similar looking gems. Learn how to analyze this property....
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What is a Trapiche Emerald?
Trapiche emerald gems are some of the world's rarest emeralds. Learn where they're found and how their characteristic “spoked wheel”...
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Descriptive Crystallography for Gemologists
Crystallography is the study of crystalline solids. Learn the most common terms gemologists use to describe the structure of crystal...
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Gemstone Optics: The Basics
Accurately measuring optical properties is critical for identifying gemstones. This article covers the basic terminology and concepts of gemstone optics....
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What is Gemstone Cleavage?
Gemstone cleavage is a break in a crystal along internal planes. Learn the science behind this and the difference between...
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What is Gemstone Luminescence?
Gemstone luminescence is a glow that occurs when certain stones are subjected to energy such as UV light. This effect...
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Evaluating Gem Color: Hue, Tone, and Saturation
Accurately describing gem color is critical to determining a gemstone's value. Learn how to grade hue, tone, and saturation and...
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Understanding Color in Gemology
The color of a mineral or gemstone is one of the primary attributes used for identification,but it is, unfortunately, one...
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