L.A. Groat (editor). Geology of Gem Deposits (Short Course Series Volume 37). Quebec (Mineralogical Association of Canada). 288 pp. Price US$50.00. ISBN 978-0-921294-37-5.

Abstract

Gem deposits are rare because, in general, the conditions that promote their formation are unusual. Modern geological and analytical techniques have now been applied to gem occurrences in Canada and elsewhere throughout the world, leading to some radical changes from a geological viewpoint. This volume looks at gemstones from a geological perspective and reviews current concepts on the origin and emplacement of diamond, ruby sapphire, emeralds and other coloured gems. It is appropriate that the book opens with a chapter on diamond, not only because of its importance as a gemstone but also because in recent years Canada has developed into a major diamond-producing country, contributing 14% by value of the world’s diamond production. Thomas Stachel provides a masterly summary, covering the origin of diamond in the Earth’s mantle, the various diamond ‘Types’ and the stable isotope composition of diamonds, and gives a detailed account of mineral inclusions in diamond and inclusion-based geothermometry. Surprisingly, there is no appreciable mention of the Canadian diamondiferous kimberlites of the Slave craton, though these deposits are mentioned in the references. The geology …