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

The East African nation of Tanzania has great gem wealth.

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

The stony-iron meteorites known as pallasites are famed for the areas of yellowish green olivines they contain.

The Ponderosa mine is now producing commercial quantities of the gem-quality labradorite feldspar known as sunstone.

Gem-quality rubies and pink to purple sapphires are being recovered from the Luc Yen and Quy Chau mining regions of Vietnam.

Today, only by combining different gemological tests with years of practical experience, can a conclusive determination of the origin of a sapphire be made.

In addition to its rich history, the Dresden Green offers an opportunity to gain information about how to distinguish natural from laboratory-irradiated green diamonds.

Unusually vivid tourmalines from the state of Paraiba, in north eastern Brazil, have attracted great interest since they first appeared on the international gem market in 1989.

This article discusses the history of the Majorica imitation pearl, the manufacturing and marketing processes, and the separation of the Majorica product from its cultured counterparts.

Blue diffusion-treated sapphires are becoming more prevalent than ever before.

Many deposits of jadeite have been found in Guatemala during the last two decades.

Gem-quality zircon from a relatively underdeveloped locality in the Harts Range of central Australia is described.