This article illustrates the various features in filled diamonds and explores the best techniques for examining them.

The emeralds of the Ural Mountains, in what is now called the Russian Federation, have been known for more than 160 years.

The history of Baja California has been closely tied to the exploitation of pearls since the 16th century.

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

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

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.

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.

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.