Physics

Lanthanum

Lanthanum

Lanthanum Definition Lanthanum is a soft, malleable, silvery-white metallic element of the lanthanide series. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which lanthanum is the first and the prototype. It is al.....

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Yttrium

Yttrium

Yttrium Definition Yttrium is a silvery metallic element found in the same ores as elements of the lanthanide series. It is almost always found in combination with lanthanide elements in rare-earth minerals, and is never found in nature as a free element. Y is the only stable isotope, and the onl.....

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Bastnäsite

Bastnäsite

Bastnäsite Definition Bastnäsite is a rare yellow to reddish-brown mineral consisting of a carbonate of fluorine and several lanthanide metals. It occurs in association with zinc and is a source of the lanthanides. Bastnaesite is commonly associated with other rare-earth-bearing minerals such a.....

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Neodymium

Neodymium

Neodymium Definition Neodymium is a shiny, silvery metallic element of the lanthanide series. It is present in significant quantities in the ore minerals monazite and bastnäsite. Its atomic number 60; atomic weight 144.24; melting point 1,024°C; boiling point 3,027°C; specific gravity 6.80 or .....

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Scheelite

Scheelite

Scheelite Definition Scheelite is a white, brownish, or greenish mineral, usually fluorescent, consisting of calcium tungstate in tetragonal crystalline form with some tungsten often replaced by molybdenum: occurs principally in contact metamorphic rocks and quartz veins, and is an important sour.....

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Tungsten

Tungsten

Tungsten Definition Tungsten is a hard, gray to white metallic element that is very resistant to corrosion. It has the highest melting point of all elements, and it retains its strength at high temperatures. It is also known as wolfram. Tungsten is a rare metal found naturally on Earth almost exc.....

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Rhenium

Rhenium

Rhenium Definition Rhenium is a very rare, dense, silvery-white metallic element with a very high melting point. It is used to make catalysts and electrical contacts. Its atomic number 75; atomic weight 186.2; melting point 3,180°C; boiling point 5,627°C; specific gravity 21.02; valence 1, 2, 3.....

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Diorite

Diorite

Diorite Definition Diorite is a gray, coarse-grained plutonic rock. Diorite consists mainly of sodium-rich plagioclase and one or more mafic minerals such as biotite, hornblende, or pyroxene. It is the coarse-grained equivalent of andesite. Diorite may contain small amounts of quartz, microcline,.....

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Monzonite

Monzonite

Monzonite Definition Monzonite is an igneous rock composed chiefly of plagioclase and orthoclase, with small amounts of amphibole, pyroxene, and biotite. Monzonite contains little or no quartz. The rocks are of granitic appearance, usually rather dark grey in colour and fine to moderately coarse .....

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Syenite

Syenite

Syenite Definition Syenite is a light-colored, coarse-grained igneous rock consisting primarily of alkali feldspar together with some mafic minerals, especially hornblende. Unlike most igneous rocks, syenite has little or no quartz. Some syenites contain larger proportions of mafic components and.....

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Chondrite

Chondrite

Chondrite Definition Chondrite is a stony meteorite that contains chondrules embedded in a fine matrix of the silicate minerals olivine and pyroxene. About 85 percent of all meteorites are chondrites. One of their characteristics is the presence of chondrules, which are round grains formed by dis.....

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Meteorite

Meteorite

Meteorite Definition Meteorite is a meteor that reaches the Earth’s surface because it has not been burned up by friction with the atmosphere. Meteorites are believed to be fragments of comets and asteroids. Meteorites are pieces of other bodies in our solar system that make it to the groun.....

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