Die erste Auflage dieses Buches ist seit sieben Jahren vergriffen. Die Frage, ob eine neue Auflage gemacht werden sollte, wurde von allen Seiten bejaht. Ich möchte glauben, daß die Überlegungen, die mich 1949 zur Herausgabe bewogen haben (s. Vorwort zur 1. Auflage), auch heute noch bestehen, ja, daß eine Darstellung der unter dem Begriff "Mineralogie" zusammengefaßten Wissensgebiete gerade bei der rapiden Entwicklung dieser Gebiete besonders notwendig erscheint. Diese Erweiterung unseres Wissens hatte zur Folge, daß ich mir nicht mehr zutraute, das Gesamtgebiet neu zu bearbeiten. Prof. ZEMANN hat es freundliehst übernommen, den 1., kristallographischen, Teil zu revidieren, er hat viele wichtige Verbesserungen angebracht. 

Nearly every mineralogy, metallurgy, chemistry, and physics textbook now contains a short section on crystallography. These abbreviated treatments can hardly be expected to present more than some of the conclusions of the science. Something was plainly needed to explain the reasoning leading to these conclusions. This book was written to supply a fuller account of the subject.

One purpose of this book is to advance the idea that many minerals are not fixed and simple in composition. Some years ago Professor D. Jerome Fisher of the University of Chicago pointed out that the writer's Elements of Optical Mineralogy had made such a treatment available to advanced students for some years, but that no elementary textbook, in any language, presented the subject in a similar way. A result of Dr. Fisher's suggestion has been the preparation of this volume.

The Precambrian crust of Saudi Arabia, the eastern Sudan and Egypt consists of abundant granites and granodiorites, arc-type volcanics, and well-authenticated ophiolites. The metamorphic grade is generally low. Archaean remnants are absent. In contrast, the Precambrian in the Mozambique belt in Kenya and Tanzania consists of high-grade metamorphic rocks, contains much reworked Archaean basement, and few granitic or granodioritic plutons. It is proposed that there is a transition from crust formed by successive accretion of island arc/back arc complexes in the north to products of collisions between plates carrying Archaean continental crust in the south. The collision led to Himalayan-type crustal thickening, deep erosion and isostatic uplift, exposing deep-crustal rocks. <...>