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Mineral composition is one of the major defining characteristics of rocks. Rock textures and structures are also important defining characteristics. It is not surprising that the number of rock types is very large indeed, given the large number of different minerals that occur in nature, the different conditions under which they form, and the different proportions in which they can combine to form aggregates with various textures and structures. Helping students to understand the properties, classification, origin, and significance of minerals and rocks is the major emphasis of this text.

geosphere

ssss1 Standard cross‐section model of the geosphere. Major compositional layers are shown on the left: core (red shade), mantle (brown shade), and continental and oceanic crust (blue shades). Major mechanical layers are shown on the right: inner core and outer core (red shades), lithosphere (light brown), mesosphere (dark brown), and asthenosphere (burnt orange).