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.
Descriptive Crystallography for Gemologists
Gemologists deal with many crystalline minerals. Learn the most common terms used in crystallography to describe their appearance and structure.
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 avoid some common pitfalls.
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 others occur only in one.
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.
Optics in Gemology
The optical properties of gemstones and minerals are determined by their crystallographic symmetry. Learn more about optics and gem identification here!
Phenomenal Gems - Unique Phenomena in Gemstones
Phenomenal gems seem to do magical things with light. Learn the optical effects behind these displays and how to judge the value of these beautiful stones.
Gemstone Thermal Properties
Non-destructive tests are critical for gemologists trying to identify gems. Learn how measuring thermal properties, especially thermal inertia, can help.
What are Gemstone Enhancements?
Gemstone enhancements improve the appearance and wearability of gems. Learn about the most commonly used procedures and frequently treated types of gems.
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 of the least diagnostic and useful
What is Gemstone Luminescence?
Gemstone luminescence is a glow that occurs when certain stones are subjected to energy such as UV light. This effect can help gemologists identify gems.
What is Gemstone Cleavage?
Gemstone cleavage is a break in a crystal along internal planes. Learn the science behind this and the difference between cleavage, fracture, and parting.
Gemstone Optical Properties
Learn how gemstone optical properties, like refractive index and pleochroism, help gemologists with identifications and lapidaries choose gem cuts.
What is Gemstone Pleochroism?
Some gems show pleochroism, two or three different colors depending on the viewing angle. Learn why this occurs and how it helps gemologists identify gems.
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” patterns are formed.
Gemstone Color Change Phenomena
Why do certain gems change color under different lights? Explore gemstone color change phenomena and the difference between natural and artificial light.
