Texas Rocks and Minerals: An Amateur's Guide

BUREAU OF ECONOMIC GEOLOGY The University of Texas Austin, Texas Peter T. Flawn, Director
Guidebook 6
By ROSELLE M. GIRARD
Sketches by Bill M. Harris
February 1964 Second Printing, April 1972 Third Printing, April 1976 Fourth Printing, May 1979
This booklet has been designed to serve as a brief, simple guide that will be of help to school children, amateur collectors, and others who are just beginning to develop an interest in the rocks and minerals of Texas. It is a companion volume to Texas Fossils by William H. Matthews III published as Guidebook No. 2 by the Bureau of Economic Geology.
Numerous present and former staff members of The University of Texas contributed time and talents to the preparation of this book, and their help is gratefully acknowledged: Peter T. Flawn, Director of the Bureau of Economic Geology, Thomas E. Brown, John W. Dietrich, Alan Humphreys, Elbert A. King, Jr., Peter U. Rodda, and others, including the late John T. Lonsdale, made many helpful suggestions; John S. Harris and Miss Josephine Casey edited the manuscript; Cader A. Shelby prepared a number of the photographs; Bill M. Harris made the illustrative sketches under the direction of James W. Macon; and Cyril Satorsky designed the cover.
Roselle M. Girard
Texas has a great variety of rocks and minerals—some are common and others are not. This book is designed to acquaint you with some of them and to tell you in a nontechnical way what they are like, some of the places where they are found, and how they are used. Although we do not know exactly how all of the rocks and minerals formed, some of the ideas about their origin are mentioned.
Earth’s outer crust (thickness not drawn to scale).
Those who study the earth’s crust—its origin, history, rocks, minerals, fossils, and structure—are known as geologists . The geologists who are especially interested in a particular phase of geology , as this science is called, are given special names: those who study fossils are called paleontologists ; those who study minerals are called mineralogists ; those who study rocks are called petrologists .