Figure 1. The vivid colors seen in fine gem-quality spinel are derived from the mixing between multiple different chromophores in a range of ratios and concentrations, as in this fine 13.52 ct ...

Through extensive hands-on practice using gemstones, you will explore grading the color, clarity and cut quality of a wide range of colored stones. Coursework includes the study of the GIA Colored ...

For over 100 years, reference has been made to a unique sapphire, the color of a lotus blossom, the padparadscha. Yet the precise hue represented by this rare stone has been a subject of discussion, ...

2月生まれの方の誕生石はアメシストです。アメシストは、何千年も人々を魅了しているクォーツの紫色の変種です。ライラックから深い紫色の色相を呈するアメシストは、多くの形やサイズ ...

The northeastern portion of the state of Minas Gerais, Brazil, contains the world's greatest concentration of complex granitic pegmatites, which are especially noted for the production of gem beryl, ...

Many of the important gem minerals seen on today's market - aquamarine, tourmaline, and topaz, among others - come from an unusual type of rock known as a pegmatite. Gem-bearing pegmatites are ...

During the past 25 years, the corundum market has been transformed from one of medium to high-priced gems to one that encompasses nearly all price ranges. This transformation was caused by the ...

The soothing soft pink shades of rose quartz appeal to gem carvers and collectors. – Valerie Power, courtesy Arunashi People accept a certain amount of sand, dirt, and dust as ordinary ingredients in ...

Whether you're taking your next step in your professional journey or starting a new career, GIA courses and diploma programs prepare you for success. With curriculum developed from groundbreaking ...

Colorless to yellow to intense orange sapphire will react quite differently to light or heat depending on the nature of the material and the origin of the color. The authors determined that there are ...

Diamond “type” is a concept that is frequently mentioned in the gemological literature, but its relevance to the practicing gemologist is rarely discussed. Diamonds are broadly divided into two types ...

Designed for clients who seek in-depth insights into every aspect of a jewelry item. Comprehensive analysis of the diamonds in an item, including number of stones, shape, estimated carat weight, color ...