This is the seventh edition of a book which has been for years the "bible" of professional and amateur gemmologists, as well as retail jewellers. Originally written by Robert Webster, an expert who dedicated most of his life to the subject, this edition has been completely revised and updated by E. Alan Jobbins, Keeper of Minerals and Gemstones at the Geological Museum in London for 35 years. It includes a comprehensive glossary on all aspects of gemstones and the terms associated with them, and sections on manufactured gems, the enhancement of gem materials, and the precautions necessary to avoid damage to gemstones and jewellery during manufacturing, repairs, and cleaning.