Unusual color-change garnets.

The American freshwater pearl industry and its new entry, the freshwater cultured pearl.

Similarities between natural spinels — with intense blue color — and synthetic material, have led to difficulties in the recognition of the natural stones by traditional methods.

A review of the history of this area, its geology, and the mining methods that have predominated.

The properties of a novel gemological imitation, cobalt glass.

A report on the new synthetic ruby trade-named Ramaura.

This article focuses on Colombian emeralds and gives a detailed explanation of the oiling process as observed by the author.

This article examines the history of the Ouro Preto district as well as the geology of the area and occurrence of the topaz.

The lapidary arts of Harold and Erica Van Pelt.

The term "alexandrite effect" refers to the apparent change of color in certain minerals from blue-green or greenish violet in daylight to red or reddish violet in incandescent light.

Thailand has become the world's major source of gem ruby.

The discovery and gemological properties of gem-quality friedelite.

An examination of the challenges of carving gem-quality opal.

An overview of the many types of gem-quality material, and its inclusions, currently found in Sri Lanka.

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

An examination of the various simulants of of nephrite and jadeite, and how to separate them from jade.

The cutting of a one-kilo kunzite crystal demonstrates the problems inherent in working with this stone.

Marketed throughout the world, San Carlos material is often confused with, and sold as, peridot from localities that are better known and documented.

A review of heat treatment methods available for use on natural or synthetic corundum.

A discussion of the techniques important in producing top-quality photomicrographs.