Gems in museums
The authors and publishers are greatly indebted to the museums and owners of collections who have kindly lent the specimens reproduced in this volume, and who have given assistance in many other ways. Particular thanks are due to Dr E. Jorg of Karlsruhe (National Museum of Natural History), Dr O. Griitter of Basle (Museum of Natural History and Ethnology), Dr M. Schnetter of Freiburg im Breisgau (Town Collection), Dr M. Griinenfelder of Zurich (Mineralogical Collection, Eidgenossische Technische Hochschule) and Dr H. Dachs of Munich (Institute of Crystallography and Mineralogy, Munich University).
Mr Georg O.Wild of Idar-Oberstein has very kindly permitted us to photograph specimens of minerals belonging to his firm, as also has Mr W. Finck of Freiburg im Breisgau, who has provided specimens both from his private collection and that of his firm, Gebr. Trenkle, gem cutters and polishers, also of Freiburg im Breisgau. Mr A. Panzer of Niederrotweil am Kaiserstuhl kindly lent specimens from his private collection. The colour plates illustrating this volume were selected from a much larger number of photographs. They show, firstly, the diverse properties of minerals, and, secondly, the variety of form and colour of individual mineral species.
This volume is not intended to be a text-book, but sets out to convey an impression of the shapes and colours of minerals in their natural form. The minerals selected for particular mention in the text are those illustrated in the plates. For more detailed descriptions of the properties, occurrence and uses of minerals, gemstones and rocks, the reader is referred to the list of text-books and reference works given in the bibliography.