Nevertheless, gemologists today no longer use this term. Peridot has been used as an amulet of protection since the beginning of man’s civilization, used to dispel sorcery and magic, terrors of the night, evil spirits, melancholy and madness, as well as to sharpen the mind. Define peridotite. A peridotite is a dense, coarse-grained igneous rock, consisting mostly of the minerals olivine and pyroxene. It is a common constituent of magnesium-rich, silica-poor igneous rocks; metamorphism of some high magnesium sediments also can form olivine. According To The Continental Geothermal Gradient, Rocks Buried 80 Km S A Mass Of Peridotite Buried 80 Km Underground Beneath A Continent Would Normally Be Heated To What Temperature? Peridot was used in early Egypt as far back as 2,000 B.C.E. A peridotite is an ultramafic rock containing more than 40% olivine (Mg 2 SiO 4). Fields include peridotite, pyroxenite, dunite, lherzolite, harzburgite, wehrlite, olivine-websterite, websterite, orthopyroxenite, clinopyroxenite. Question: A. * 2004 , (Richard Fortey), The Earth , Folio Society 2011, p. 51: Gem-quality olivine is known as peridot , which has a subtle green light all its own. Partial melting of mantle peridotite Melting begins when upwelling mantle intersects the peridotite solidus. Both the western and eastern peridotite units of the Sarugawa ultramafic massif are composed of harzburgite with small amounts of dunite and minor websterite, orthopyroxenite and chromitite. The rock typically forms in volcanic pipes and is forced to the surface from great depths during a volcanic eruption. It commonly contains a few percent chromium-rich spinel as an accessory mineral. Peridotite definition: a dark coarse-grained ultrabasic plutonic igneous rock consisting principally of olivine | Meaning, pronunciation, translations and examples Peridotite. Peridotite is ultramafic, as the rock contains less than 45% silica. It has also seen some use as a garden paving stone. Iwanaidake and belongs to the western unit peridotite of the Sarugawa ultramafic massif. Kimberlite, the matrix of the diamonds in the pipe mines, is a peridotite. Peridotite. Due to its amazing appearance it is also known by the euphemism "Evening emerald" (Do remember it is not an emerald. This specimen is approximately 3 … When different peridotite compositions are compared at a given F, the Al 2 O 3 content of the melt varies monotonically with source Al 2 O 3 and appears not to be strongly affected by the Al 2 O 3 concentration of the peridotite source ; i.e. This type of igneous rock is named for peridot, the gemstone variety of olivine. Natural peridot is the August birthstone. Peridotite definition, a coarsely granular igneous rock composed chiefly of olivine with an admixture of various other minerals. Peridotite definition is - any of a group of granular igneous rocks composed of ferromagnesian minerals and especially olivine. The studied area is shown by a rectangle. Harzburgite, an ultramafic, igneous rock, is a variety of peridotite consisting mostly of the two minerals olivine and low-calcium (Ca) pyroxene ; it is named for occurrences in the Harz Mountains of Germany. Peridotite is the ultimate source of all chromium ore and naturally occurring diamonds, and of nearly all chrysotile asbestos. It is one of the main host rocks of talc deposits and platinum metals and formerly was a major source of magnesite. Supplied in a card tray with label, offered in 3 optional sizes. The Yellow Dog peridotite, thought to be approximately 1.1 Ga in age, is composed of partly serpentinized peridotite, containing 40 to 50 percent olivine (1/2 to 2/3 serpentinitzed) and 30 percent pyroxenes consisting of subequal amounts of orthopyroxene and clinopyroxene. Pharaohs and leaders, including Cleopatra, heavily used peridot to adorn their robes and goblets, believing that peridot had magical powers. Peridotite is an igneous rock that is made up primarily of olivine and pyroxene. The noun peridotite can be countable or uncountable.. The T, P and % melting A general term for a coarse-grained plutonic rock composed chiefly of olivine with or without other mafic minerals such as pyroxenes, amphiboles, or micas, and containing little or … Peridotite: Mineral information, data and localities. Fresh dunite is used in parts of glass furnaces. Peridotite (per-RID-a-tite) is very low in silicon and high in iron and magnesium, a combination called ultramafic. However, in more specific contexts, the plural form can also be peridotites e.g. Pyroxenite Composition Pyroxenite composition is contain at least 90 percent pyroxene group minerals, such as as augite, diopside, hypersthene, bronzite or enstatite.Pyroxenite also contain olivine and oxide minerals. It has a porphyritic texture, with large, often rounded crystals (phenocrysts) surrounded by a fine-grained matrix (groundmass). Peridotite, found in Finland, is a dense, coarse grained igneous rock. Worn around the neck or bound to the left arm, it should always be set in … peridotite (pĕr'ēdō`tīt): see olivineolivine , an iron-magnesium silicate mineral, (Mg,Fe)2SiO4, crystallizing in the orthorhombic system. These xenoliths often contain crystals of olivine with a color and clarity that is suitable for use as a peridot gemstone. Kimberlite, also called blue ground, a dark-coloured, heavy, often altered and brecciated (fragmented), intrusive igneous rock that contains diamonds in its rock matrix. Peridotite sentence examples peridotite Tremolite-schist and anthophyllite-schist are in nearly all cases the representatives of the ultra-basic igneous rocks such as peridotite in regions of high metamorphism. Peridotite is a generic name used for coarse-grained, dark-colored, ultramafic igneous rocks. . See more. It is commonly used in saunas due to certain porpertie. The Western tradition suggests the August borns to … A general term for a coarse-grained plutonic rock composed chiefly of olivine with or without other mafic minerals such as pyroxenes, amphiboles, or micas, and containing little or no feldspar. the peridotite family Under this group are comprised all of those granular igneous rocks composed of ferromagnesian minerals alone, or in which the amount of detectible feldspar is so small as to be entirely negligible as a component, and in which the mineral grains are sufficiently large to be determined. Peridotite is the plutonic rock beneath the Earth's crust located in the upper part of the mantle. Peridotite is a derived term of peridot. Noun ()A transparent olive-green form of olivine, used as a gem. It is frequently used for countertop and flooring materials, gravestones, and exterior and interior wall materials. It is noted for its low silica content, and contains very little or no feldspar ( orthoclase, plagioclase).It is a common component of oceanic lithosphere, and is derived from the upper mantle. Peridotite Peridotite is a dark-colored, coarse-grained igneous rock believed by many scientists to be the primary rock of the exterior of Earth [1]'s mantle. in reference to various types of peridotites or a collection of peridotites. A peridotite is an ultramafic rock containing more than 40% olivine ( Mg2SiO4 ). Peridotites usually contain olivine as their primary mineral, frequently with … ..... Click the link for more information. Peridot has been in use for many thousands of years, and was historically called Olivine.It is an important crystal to use for cellular rejuvenation, and to help the problems associated with These rock specimens are ideal teaching aids or collectors specimens. (geology) A rock consisting of small crystals of olivine, pyroxene and hornblende; the major constituent of the Earth's mantle. Peridotite is the general name for the ultrabasic or ultramafic intrusive rocks, dark green to black in color, dense and coarse-grained texture, often as layered igneous complex. This term is used by shrewd salesmen to improve their sales pitch!) Olivines (those from Earth, not from outer space) form in the Earth’s mantle. 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