"Practical Gemmology" has for decades been recognised as the standard work for those learning how to identify gems and ornamental minerals. It is recommended by educational authorities as a course textbook; it is also particularly suitable as a self-instructor for those entering or hoping to advance in the jewellery and gem trades, or for the keen amateur. The twenty-one sections comprise notes on the formation of gem materials and an additional chapter on the chemistry of gemstones. A section on luminescence and electrical effects that brings a more modern approach to this part of the subject. More information is given on the inclusions seen in gemstones and the newer synthetic stones are discussed. Increased coverage is given to the types of modern methods of colouring diamonds artificially. The methods used in cutting gemstones and details of more of the unusual gemstones now cut and polished are also discussed.