Learning Center

Advanced Gemology Topics

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

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 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.…

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…

Gemstone Radiation Treatment

Most gems on the market today receive various treatments to change their natural colors and create more desirable, salable products. Radiation…

Impurity Ions and Gemstone Colors

I’ve faced many questions about the element chromium (Cr), the red coloration of minerals, and the gemstone red beryl. One of the many causes of…

Identifying Garnets Simplified

Identifying garnets by species is complicated. Learn how to use refractive index, hue, and absorption spectrum readings to simply the separation…

The History of Quartz Treatment

Learn about the history of quartz treatment, including why it took so long to treat quartz with any consistency, in this informative article.

HPHT Diamond Update

Gemologists are seeing more and more HPHT diamonds. While detection equipment is costly, you can assess the likelihood of treatment without it.…