ROCKS AND MINERALS are a fundamental part of the Earth’s crust. Collecting and studying them can be both a rewarding and an absorbing hobby. This can involve traveling to exciting places, a lot of research, and some time spent cataloging and displaying finds. As your collection grows, you can exchange material with other collectors and purchase rare or exceptional specimens from mineral dealers <...>

A mineral is a naturally occurring solid with a specific chemical composition and a distinctive internal crystal structure. Most minerals are formed inorganically but some, such as those found in bone, are formed organically (by living organisms). <...>

One of the nine known planets that revolve around the Sun, the Earth is thought to be about 4.6 billion years old. Geology is the study of the history of the Earth. Because rocks can provide valuable information about the Earth in previous times, geologists study them and work out the processes and events that produced them. As we can currently bore only a few miles into the crust, or outer shell, we cannot sample rocks from the mantle (the inner shell) directly. The rocks and minerals shown here come from many locations and introduce important features that are explained in more detail later in the book.

Nothing is as important in the natural world as our own earth and the rocks beneath our feet. So it was inevitable that the Golden Nature Guides include an introduction to rocks and minerals. The task of selecting, describing, and illustrating minerals,  rocks,  and  geologic  structures  has many  inherent  difficulties.  We are grateful  to  our  colleagues and to other experts who have helped. May we particularly thank members of the Geology Department of the University of Illinois: Drs. Chapman, Droste, Grim, Hagner,  Henderson,  Merrill,  Wanless,  and  White,  and Drs. Collinson, Swann, and Willman of the Illinois State Geological Survey for specimens and slides, and for information  and   encouragement.   Some  specimens  came from University of  Illinois Natural  History Museum  and departmental collections; some from Ward's Natural Science Establishment. The gem collections at the Chicago Museum of Natural History were invaluable. Fine Koda-chromes were provided by Scott Lewis. Maps came largely from information in the Minerals Yearbook of the Bureau of Mines, and from other maps and publications of the United States Geological Survey.