New Jersey Scuba Diving

Rock is an aggregation of solid matter composed of one or more of the minerals forming the earth's crust. The scientific study of rocks is called petrology. Rocks are commonly divided, according to their origin, into three major classes - igneous, sedimentary, and metamorphic.

Not all rock-like materials are created by nature. Almost all civilizations have depended to some extent on artificial building materials, the most common of which are concrete, brick, and asphalt.

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