Yogo Gulch, discovered more than 100 years ago, is one of four major sapphire-producing areas in Montana, United States.

Large quantities of rubies—both rough and faceted—from a commercially important new source in Myanmar (Burma) have been available on the Bangkok market since 1992.

Primary occurrences of ruby, pink sapphire, sapphires of other colors, and spinel have been found in marbles in the Ural Mountains.

How GIA’s Gem Trade Laboratory grades colored diamonds, including an expanded color grading terminology, is explained

Many deposits of gem corundum are associated with alkali basalt.

Inclusions of native copper and tenorite (CuO) were found in grayish green elbaite from São José da Batalha, Paraíba, Brazil.

Northern Vietnam began producing significant quantities of rubies and fancy sapphires in the late 1980s.

Russian-grown gem-quality synthetic diamonds are being sold for jewelry; this article presents the results of a gemological examination of a group of yellow samples.

Renewed interest in large-scale commercial mining of Montana sapphires motivated a detailed study of the heat treatment of sapphire from the Rock Creek deposit.

Sri Lanka is world famous for its gem wealth, but the actual extent of the deposits has never been determined.

Although the reign of King Edward VII of Great Britain was relatively short (1902-1910), the age that bears his name produced distinctive jewelry and ushered in several new designs and manufacturing techniques. During this period, women from the uppermost echelons of society wore a profusion of extravagant jewelry as a way of demonstrating their wealth and rank. The almost exclusive use of platinum, the greater use of pearls, and the steady supply of South African diamonds created a combination that will forever characterize Edwardian jewels. The Edwardian age, truly the last era of the ruling classes, ended dramatically with the onset of World War I.

De Beers has produced a faceted synthetic gem-quality diamond that could go unrecognized without careful gemological testing.

Strongly etched prismatic crystals of yellow, green, and pale blue gem beryl have been quarried from a pegmatite dike in Luumäki, Finland.

Blue diffusion-treated sapphires have become a subject of considerable controversy since their introduction in significant quantities a few years ago.

After almost 75 years of inactivity, the deposits of boulder opal in Queensland, Australia, began to attract new interest in the 1960s and 1970s.

Diamond production’s future appears to belong less to Africa and more to Australia, Canada, and the Russian Federation, according to this overview of geologic trends in the industry.

Verifying the gold content of karat-gold jewelry is a problem for the entire industry.

The "bleaching" treatment of jadeite jade has become prevalent in higher- as well as lower-quality material.

Burma, now named Myanmar, has for centuries been considered the world's preeminent source of fine rubies.

The gemological properties of a new ruby imitation, produced by dyeing natural colorless to pale-colored corundum, are described.