Pink-to-red coral has a long history as an ornamental gem material in jewelry, carvings, and sculptures. However, due to a variety of environmental and legal factors, the supply of high-quality, ...

GIA Instruments works hand-in-hand with GIA’s laboratory, education and research teams, as well as the jewelry trade to develop the instrumentation you need to prepare you for the challenges of ...

The separation of naturally colored lavender jadeite from color-treated material is a problem that has long plagued gemologists. One theory is that the dyeing agents being used are of an organic ...

CARLSBAD, California – January 14, 2025 - The Gemological Institute of America (GIA) has announced the planned retirement of its president and CEO, Susan Jacques, at the end of 2025. The Institute has ...

Established in 1931, the Gemological Institute of America (GIA) is the world’s foremost authority on diamonds, colored stones, and pearls. A public benefit, nonprofit institute, GIA is the leading ...

Diamonds have a long history as beautiful objects of desire. In the first century AD, the Roman naturalist Pliny stated: “Diamond is the most valuable, not only of precious stones, but of all things ...

黄水晶是一种精美通用的宝石，可用于制作珠宝首饰，并且只需适当的护理。 – Robert Weldon（罗伯特·韦尔登） 莫氏硬度用以衡量宝石和矿物的硬度。 这些数字以一种矿物可被其他矿物划伤的 ...

Fine-color, large, and eye-clean (lacking visible inclusions) rubies like this 11.01carat (ct) stone from Myanmar (formerly known as Burma) are extremely rare and valuable. – Photo: Robert Weldon/GIA.

As a consumer, you will regularly encounter in the marketplace gems that have been treated to change their appearance. A topic that often comes up is whether a particular gemstone is or isn’t treated.

This sapphire from Kashmir has an intense velvety blue color. – Photo: Robert Weldon/GIA. Sapphire is one of the Big three of jewelry colored gemstones—the other two are ruby and emerald. A durable ...

The Diamond and Diamond Grading eLearning course brings to life the skills needed to grade the color, clarity and cut of diamonds through video, graphics, images and text.