There are many books about geology explaining the identification and classification of rocks and describe the underlying geologic principles. Almost any recent general book on geology would help a rock collector. We will not go into this in great details here because it would take up volumes of pages. A cheap geology book will suit most occasions.

Geologic maps, which are useful guides for collecting, are also excellent identification aids. They show the distribution and extent of particular rock types or groups of rock types. Depending on size and scale, the maps may cover large or small areas. Most have brief descriptions of the rock types. Some are issued as separate publications; others are included in books.

Comparing one's own specimens with those in a museum collection can help in identifying them. Most large rock collections are well labeled. Small rock collections abound in libraries, schools, public buildings, small museums, and private homes.