A second edition, in two parts, of Volume 1 of this well-known reference series. This part deals with the disilicates and ring silicates, including the epidote, melilite, cordierite, and tourmaline groups. In addition to minerals dealt with in the first edition, some of the rarer but typical minerals of calc-silicate rocks and the accessory minerals of nepheline-syenites and related rocks have been included. The orthosilicates, in particular the olivine, garnet and humite groups, are covered in Volume 1A.

In the years since the first edition was published, the quality and scope of research on disilicates and ring silicates has grown enormously and has given rise to a wide variety of literature. This book, which has been completely re-written and considerably expanded, summarizes the important research results and presents them in an organized fashion.

Each mineral chapter is divided into sections on structure, chemistry, optical and physical properties, distinguishing features and paragenesis. Each chapter is headed by a brief tabulation of mineral data and a sketch showing optical orientation, and concludes with full references to the literature. Diagrams of the crystal structures are presented and are followed by discussion of the structural features. The chemical sections include a large number of analyses from which structural formulae have been calculated, illustrating the chemical and paragenetical variation exhibited by each mineral; phase equilibria in relevant systems are fully considered. In the sections on optical and physical properties, particular attention is paid to the correlation of these properties with chemical composition. The principal modes of occurrence are described and discussed in the paragenesis sections; here again correlation with chemistry is emphasized.