Frank Wigglesworth Clarke was a leading figure in American chemistry and mineralogy in the late 19th and early 20th centuries, and this book collects his influential analyses of rocks and minerals from the US Geological Survey. Featuring detailed descriptions of hundreds of specimens, this book is an essential resource for geologists and mineralogists as well as historians of science. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.