The September birthstone is sapphire – a gem that’s been cherished for thousands of years. Although the term sapphire usually refers to the blue variety of corundum (ruby is the red variety), this ...

Gemological Characterization of Montana Sapphire from the Secondary Deposits at Rock Creek, Missouri River, and Dry Cottonwood Creek Examines the mining history and geological characteristics of the ...

The Thai city of Chanthaburi is a well-known international trading hub for colored gemstones but was once an important corundum mining center. In recent decades, mining activity in the area has ...

The GIA Board of Governors - Front Row from left to right: Samantha Ravich, Ph.D., Dave Bindra, Susan Jacques, Lisa Locklear (Board Chair), Stephen Kahler (Vice Chair), Barbara Dutrow, Ph.D., Russell ...

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.

GIA’s D-to-Z color grading system is based on the relative absence of color. GIA’s Fancy colored diamond color grading is based on the presence of color. GIA describes color in terms of hue (the color ...

周囲を南アフリカ共和国に囲まれた内陸国のレソトの人里離れたMaluti（マルチ）山地は最も景観の美しい地域だ。 これらの山々からは、世界中の人々が手に入れたいと望むIIa型ダイヤモンド ...

Emerald, the birthstone for May, has been beloved for millennia, evoking rebirth and renewal. Widely regarded as the definition of green, emerald is the perfect color for spring. From the poetic ...

Observations of Oval-, Pear-, and Marquise-Shaped Diamonds: Implications for Fancy Cut Grading Presents findings from observations of oval-, pear-, and marquise-shaped diamonds, laying the groundwork ...

GIA programs and courses are offered year-round on a rolling basis at GIA campuses around the globe. This enables students to jumpstart their gem and jewelry career studies at the soonest, most ...

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 ...

GIA’s diverse course offerings will help prepare you with the knowledge and skills needed by industry employers today.