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igneous rock
igneous rock One of three major classes of rock produced by the cooling and solidifying of molten magma. All igneous rocks are crystalline and most resist erosion. Extrusive, or volcanic, igneous rocks, such as basalt, form by the rapid cooling of molten material at the surface. Intrusive, or hyper...
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petrology
petrology branch of geology specifically concerned with the origin, composition, structure, and properties of rocks , primarily igneous and metamorphic, and secondarily sedimentary. It includes petrography, the systematic description and classification of rocks using microscopic examination of roc...
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Sela
Sela or Selah [Heb.,=rock], in the Bible, unidentified town, S of the Dead Sea. Amaziah captured it and renamed it Joktheel. Some identify Sela with Petra . Sela in the first chapter of Judges seems to be another rock.
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rock
rock 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.
Igneous Rocks
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Cephas
Cephas , in the Gospels, Jesus' name for St. Peter. It is a transliteration of the Aramaic word for rock, and identical in meaning with "Peter" in Greek.
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metamorphic rock
metamorphic rock An aggregate of minerals formed by the recrystallization of pre-existing rocks in response to a change of pressure, temperature, or volatile content. Metamorphic rocks can generally be divided into four types: (a) regional metamorphic rocks, formed in response to changes leading to ...
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schist
schist , metamorphic rock having a foliated, or plated, structure called schistosity in which the component flaky minerals are visible to the naked eye. Schists are distinguished from the other foliated rocks, slates and gneisses, by the size of their mineral crystals; these are larger than those ...
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sedimentary rock
sedimentary rock Type of rock formed by deposition of sediment derived from pre-existing rocks, which may have been sedimentary, igneous or metamorphic. Most sediment accumulates on the bed of the sea, having been dumped there by rivers, or having accumulated as dead sea creatures fall to the seafl...
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joint
joint in geology, fracture in rocks along which no appreciable movement has occurred (see fault ). Nearly vertical, or sheet, joints that result from shrinkage during cooling are commonly found in igneous rocks. Similar joints occur in thick beds of sandstone and gneiss, with the sheets resembling...
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rock crawler
rock crawler name applied to the slender, wingless insects of the family Grylloblattidae in the order Orthoptera. They have long antennae and range in length from 1/2 to 1 in. (15-30 mm). Rock crawlers occur at altitudes of 1,500 to 6,500 ft (450-2,000 m), where they live in caves, under rock...
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