Learning Center

Advanced Gemology Topics

Advanced gemology topics on a wide variety of technical subjects such as gemstone treatments and inclusions.
Gemstone Physical Properties

The optical properties of gems attract our eyes and can give a cut stone a unique character. However, gemstone physical properties are also important.…

Gemstones and Refraction Liquids

Gemologists use refraction liquids to identify gemstone refractive indices (RI). Learn about the properties of these liquids and safe RI testing…

HPHT Diamond Treatments

HPHT diamond treatments can only be positively identified with costly equipment. However, you can learn to assess the probability that a stone…

Quartz Color Treatments

Quartz color treatment results vary due to the stone’s origin. Learn the effects you can achieve with different materials and radiation and heat…

Gemstone Radiation Treatment

Gemstone radiation is a common but little understood technique for altering gem colors. Learn how it works and what gems usually receive this treatment.…

Gemstone Color Change Phenomena

Frequently, people ask me to explain how gemstone color change works. Some stones can change color under different light sources. Although the…