This major revision takes place 38 years after the publication of the first edition. This volume in the second edition of the Rock-Forming Minerals is devoted entirely to the feldspar minerals. The text has been completely re-written and very much expanded, incorporating the advances in knowledge and understanding arising from the new and improved techniques for study of minerals that have developed over the decades between editions. The authors have maintained the general approach used in the other volumes, summarizing important research results and presenting them in an organized fashion.
Each chapter is headed by a brief tabulation of mineral data and sketches showing optical orientation, and contains full references to the literature. Diagrams of crystal structures are presented and followed by discussion of the structural features, making use of data from spectroscopic as well as diffraction experiments.. The chemical sections include many analyses from which structural formulae have been calculated, illustrating the range of chemical and paragenetic variation exhibited by each minerals: also the results of P-T experiments and thermochemical and computer modelling techniques. Compared with the first edition, greater emphasis is given to diffusion, chemical alteration and surface studies, and the use of isotope ratios to unravel thermal histories. The section of optical and physical properties include much information gained by electron microscopy, particularly about fine-scale twinning, exsolution, domain and deformation textures. The principal modes of occurrence are described in the paragenesis sections emphasizing correlations with chemistry and structure.

Rock-Forming Minerals is a standard reference work for professionals in mineralogy, petrology and geochemistry, as well as having a wide appeal as a reference work for postgraduate research students and research workers in related fields.