Description:Since it was first published in 1962 'Gems' has become universally recognised as the most comprehensive and authoritative treatise on gem materials in the English language. This sixth edition, has been revised for relevance to today's practice and includes an expanded encyclopedic section.'Gems' caters for the professional jeweller and student gemmologist, collector of gems and those with an insatiable interest in precious stones. * Descriptive account of all gem materials used as ornament, along with their synthetic counterparts * Contributing authors, at the top of the field, bring the latest developments to the reader* The only encyclopedic reference for gemstones