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.

You are sitting on a rock right now. It is a big rock, so big that you, your classroom, your school, your town, and everything else—zebras, apple trees, polar bears, sneakers—can sit on top of it. We call it the Earth, but it is really just a big rock surrounded by empty space.
This rock is important. On it sits every plot of land that will grow your food, every drop of oil that will power your cars, every person you will ever know. On this one rock, you will spend every moment of your life.

Small children can distinguish different animal species from one another. Children encounter a wide range of plant and animal species in various ways: in illustrated books, in stories, in school, while drawing or engaged in handicrafts, and so on. From childhood on we are trained to distinguish plant and animal species from each other. But what is the situation with rocks and minerals? Rocks are simply “stones” or “rocks,” and “crystals” are understood to be simply well-formed and transparent rock crystals (quartz). We are not exposed to ways to engage with rocks to identify and classify them. That is certainly one initial disadvantage, even though children are usually fascinated by rocks. Place a small child on a gravel bank, and you will enjoy some quiet for quite a while. Geology is either not taught at all in schools, or taught very little. Since the subject matter is so complex, students (and frequently teachers) struggle to master the concepts. Even so, we are ready to face the world of rocks. <...>

The term geology is a combination of two Greek expressions: “Geo” refers to the Earth, and “logos” refers to the logic and language used to explain your observations. So think of geology as a way to organize and explain the Earth processes that we see all around us. For some of the strange shapes we see, an educated explanation would be great. Most of what we know is good guesswork, based on lab experiments and inferences that take many detailed drawings to explain and a lifetime to understand. Fortunately, the more you see, the better things fall into place. <...>