All rocks fall into the three main categories of igneous, metamorphic or sedimentary. These rocks vary widely in physical appearance and location and their formation patterns differ, as well: igneous rocks form cooling m... More »

The three classes of rocks are sedimentary, metamorphic and igneous. The most significant differences found among these the three types have to do with how the rock is formed. More »

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The three major types of rocks are igneous, sedimentary and metamorphic. Formed deep inside the Earth, igneous rocks form when a melted rock cools and solidifies. This liquid rock is magma, and the rate of cooling determ... More »

Geology.com offers many pictures of rocks, divided into their fundamental categories of igneous, metamorphic and sedimentary. The igneous rock section divides the rocks into extrusive and intrusive types, with special se... More »

www.reference.com Science Earth Science Geology

The three classes of rocks are sedimentary, metamorphic and igneous. The most significant differences found among these the three types have to do with how the rock is formed. More »

www.reference.com Science Earth Science Geology

Four types of pyroclastic materials include ash, lapilli, lava blocks and floating rocks. Pyroclastic materials are ejected during a volcano. Ash is the most common type of pyroclastic material. More »

The three major types of rocks are igneous, sedimentary and metamorphic. Formed deep inside the Earth, igneous rocks form when a melted rock cools and solidifies. This liquid rock is magma, and the rate of cooling determ... More »