Bentonites are specific types of clay, commonly formed by weathering of volcanic ash. Bentonites can adsorb more water and other substances than other clays. Because of their unique properties, great abundance, and relatively low cost of exploitation and production, bentonites are used in numerous applications. This publication introduces (data) and discusses a set of 40 bentonite/clay samples from all over the world. It includes compositional and mineralogical data for these samples, making it a valuable reference on bentonite clays worldwide. Finally, the expert authors provide information on the wide range of bentoniteapplications in various fields, which has rarely been compiled in a single volume before.

The first part of this book presents an overview of the world of rocks and their setting in Earth. The genesis of magmatic, sedimentary and metamorphic rocks is described in terms of modern concepts of plate tectonics. The most important characteristics of the rock-forming minerals necessary for identification and characterization, as well as the classification procedures recommended by the International Union of Geosciences, are summarized. The structure and fabric of rocks, i.e., the way in which the component mineral grains are assembled, are documented and dealt with as a direct consequence of those specific and distinct processes that create the contrasting groups of magmatic, sedimentary and metamorphic rocks. The second and major part of this book presents ca. 450 different types of rocks in structured, systematic order. Representative, detailed and diagnostic photographs of hand specimens are combined with concise descriptions for quick and effective reference. At the end of the book the most importantmacroscopic properties of the rock-forming minerals are tabulated, and flow charts are provided as an aid to identification. A summary index of all minerals mentioned in this book together with their chemical formulae is also provided as a quick reference guide. A first German edition of this book was published in 1987, reprinted several times and even translated into Spanish and Italian. Expanded and updated editions followed in 2014, 2016 and 2024. This English edition builds on the 2024 German volume but had to cope with the difficulties of using and defining terms like fabric, texture and structure for an international readership. Texture, in particular, has been used withcompletely different meanings in different languages and disciplines. This book complies with the recommendations of the International Union of Geosciences. This book addresses students and professional as well as-non-professional geoscientists, both as an initial introduction to the world of rocks and as a quick diagnostic reference guide in the field and laboratory.