gems, jade, nephrite, jadeite, fei cui, Australia, Burma, Japan, Guatemala, British Columbia, New Zealand, Philippines

Following a review of the properties of nephrite and jadeite, Ball discusses the geology of the nephrite de-posits in Australia. In New South Wales, the nephrite occurs in ultramafic rocks, while in South Australia it is associated with metamorphic rocks that were later recrystallized. The author states that there are no known economically important occurrences of jadeite in Australia. This discussion is followed by a description of jadeite from Burma, Japan, and Guatemala and of nephrite from British Columbia, New Zealand, and the Philippines.. The remainder of the article reports on a study of fracture surfaces in both minerals. Jadeite features tri-angular cleavage fractures, while nephrite has fibers and bundles extending from the surface. Thirteen scan-ning electron micrographs, including five of jade sub-stitutes, illustrate these features. A helpful bibliography is included.