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 ...

GIA’s laboratory in Bangkok, Thailand conducts research and provides services such as diamond grading and origin determination, colored stone grading and origin determination and pearl identification ...

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 ...

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 People's Republic of China has recently placed a high priority on identifying and developing its gemstone resources. Initial exploration by teams of geologists throughout China has identified many ...

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 ...

Since late 2007, rubies and sapphires have been mined by hand methods from both eluvial and primary deposits at Winza in central Tanzania. The gem corundum is related to “dikes” of amphibolitic rocks ...

Synthetic diamond growth was first documented in 1952 by William Eversole of the Union Carbide Corporation, but it took another two decades before GIA issued the first grading report for a ...

5月の誕生石であるエメラルドは、復活と再開を連想させる宝石であり、千年以上もの間こよなく愛されています。緑色の定義として広くみなされているエメラルドの色ほど春にふさわしい ...

This article traces the use of pearls from antiquity to the initial appearance of cultured pearls in the 1920s. The first section touches on the early fascination with pearls as revealed through ...

瑞々しい青、鮮やかなバイオレット、濃い紫色のバランスを整えたエキゾチックなタンザナイトが発見される場所は、地球上でただ一つ、雄大なキリマンジャロ山の近くにあります。

Demantoid, green andradite garnet, was discovered in the Central Ural Mountains of Russia in the mid-19th century. A favorite of the Czar's court, demantoid was another victim of the 1917 Bolshevik ...