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.
If you would like to learn more about rocks and minerals in general, the
names of several reference books are listed on page 100. In addition,
scientific reports that describe in detail many of the rocks and
minerals of Texas have been published by the Bureau of Economic Geology
of The University of Texas, the United States Geological Survey, and
other organizations. A selected list of these reports is given on pages
100-101.
Rocks and minerals are familiar objects to all of us. We pick up
attractive or unusual pebbles for our collections, we admire rocky
mountain peaks, we speak of the mineral resources of our State and
Nation. Rocks and minerals enter, either directly or indirectly, into
our daily living. From them come the soils in which grow the grains, the
fruits, and the vegetables for our food, the trees for our lumber, and
the flowers for our pleasure. The iron, copper, lead, gold, silver, and
manganese, the sulfur and salt, the clays and building stones, and the
other metals and nonmetals that we require for our way of living were
once a part of the earth’s crust.
[Illustration: Texas’ highest mountain is Guadalupe Peak, right, with
an elevation of 8,751 feet. El Capitan, left, has an elevation of 8,078
feet. These peaks in the Guadalupe Mountains in Culberson County
consist largely of Capitan reef limestone, which formed during the
Permian Period.]