The properties of a novel gemological imitation, cobalt glass.

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

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

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

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

The discovery and gemological properties of gem-quality friedelite.

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.

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 challenges of carving gem-quality opal.

How amethyst under certain conditions may turn green rather than the expected citrine-yellow.

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.