Mina Stones promotes Nigerian gems including rubellite and sapphire as well as reviving traditional skills and symbols in the creation of original jewelry.

A nondestructive rapid screening technique uses fluorescence spectroscopy to identify treated colored pearls.

Application of slight pressure perpendicular to the twinning planes reveals the unusual property of this synthetic gem.

Gamma ray spectroscopy revealed that a packet of spodumene from Brazil was radioactive.

The history of the Kashmir mines, the beautiful sapphires found there, and the outlook for the future.

A survey of the current gemological knowledge of pegmatites, including the gem varieties aquamarine, tourmaline, and topaz.

First in a series, this article reviews the exploration for gemstones and mining methods in Minas Gerais, Brazil.

Several famous and historical gemstones in the Smithsonian's collection are examined and reported on.

The final part of this series is concerned with colors explained by band theory, such as canary yellow diamonds, or by physical optics, such as play-of-color in opal.