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The following is a list of rock types recognized by geologists.There is no agreed number of specific types of rock. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe a rock type.
The use of rock has had a huge impact on the cultural and technological development of the human race. Rock has been used by humans and other hominids for at least 2.5 million years. [22] Lithic technology marks some of the oldest and continuously used technologies. The mining of rock for its metal content has been one of the most important ...
The word volcanic rock is derived from the Latin root words of Vulcan, [47] the Roman god of fire, and -ic, [48] meaning having some characteristics of. The word plutonic rock, another name for intrusive igneous rock, is derived from the Latin root words of Pluto, [49] the Roman god of the underworld, and -ic, [50] meaning having some ...
Uluru (Ayers Rock) is a large sandstone formation in Northern Territory, Australia.. Sedimentary rocks can be subdivided into four groups based on the processes responsible for their formation: clastic sedimentary rocks, biochemical (biogenic) sedimentary rocks, chemical sedimentary rocks, and a fourth category for "other" sedimentary rocks formed by impacts, volcanism, and other minor processes.
Peridotite, a type of ultramafic rock. Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are usually composed of greater than 90% mafic minerals (dark colored, high magnesium and iron content).
Physical characteristics include colour, texture, grain size, and composition. [1] [2] [3] Lithology may refer to either a detailed description of these characteristics, or a summary of the gross physical character of a rock. Examples of lithologies in the second sense include sandstone, slate, basalt, or limestone. [4]
There are also many other characteristics that serve to distinguish plutonic from volcanic rock. For example, the alkali feldspar in plutonic rocks is typically orthoclase, while the higher-temperature polymorph, sanidine, is more common in volcanic rock. The same distinction holds for nepheline varieties.
Rocks formations and the Dedo de Deus (God's Finger) peak in the background, Serra dos Órgãos National Park, Rio de Janeiro state, Brazil Raouché or Pigeons' Rock in Beirut, Lebanon Druid Arch, Canyonlands National Park, Utah, US View of Meteora, Greece Rock formations in Ongamira Valley, Sierras de Córdoba, Argentina Belogradchik Rocks, Balkan Mountains, Bulgaria "Jaws", an erosional fin ...