Physics

Gallium

Gallium

Gallium Definition Gallium is a rare, silvery metallic element that is found as a trace element in coal, in bauxite, and in several minerals. It is liquid near room temperature and expands when it solidifies. Gallium does not occur as a free element in nature, but as gallium(III) compounds in tra.....

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Mercury

Mercury

Mercury Definition Mercury is a silvery-white, dense, poisonous metallic element that is a liquid at room temperature and is used in thermometers, barometers, batteries, and pesticides. It occurs in deposits throughout the world mostly as cinnabar (mercuric sulfide). The red pigment vermilion is .....

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Uranium

Uranium

Uranium Definition Uranium is a heavy, silvery-white, highly toxic, radioactive metallic element of the actinide series. It has 14 known isotopes, of which U 238 is the most naturally abundant, occurring in several minerals. A uranium atom has 92 protons and 92 electrons, of which 6 are valence e.....

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Erbium

Erbium

Erbium Definition Erbium is a soft malleable silvery-white element of the lanthanide series of metals: used in special alloys, room-temperature lasers, and as a pigment. It is a lanthanide, a rare earth element, originally found in the gadolinite mine in Ytterby in Sweden, from which it got its n.....

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Xenotime

Xenotime

Xenotime Definition Xenotime is a phosphate mineral, similar to monazite except enriched in the heavy lanthanides and yttrium. It is a rare earth phosphate mineral. The rare earth elements dysprosium, erbium, terbium and ytterbium as well as metal elements such as thorium and uranium (all replaci.....

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Terbium

Terbium

Terbium Definition Terbium is a soft, silvery-gray metallic element of the lanthanide series. It is used in color television tubes, x-ray machines, and lasers. Its atomic number 65; atomic weight 158.925; melting point 1,356°C; boiling point 3,123°C; specific gravity 8.229; valence 3, 4. The ni.....

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Gadolinium

Gadolinium

Gadolinium Definition Gadolinium is a silvery-white, malleable, ductile metallic element of the lanthanide series that has seven natural isotopes and 11 artificial isotopes. It is a Rare Earth Element (REE) with paramagnetic properties.  On the Periodic Table its symbol is Gd and its atomic numb.....

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Limonite

Limonite

Limonite Definition Limonite is a common brown, black, or yellow amorphous secondary mineral that consists of hydrated ferric oxides and is a source of iron. It is one of the major iron minerals, hydrated ferric oxide (FeO(OH)·nH2O). It was originally considered one of a series of such oxides; l.....

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Allanite

Allanite

Allanite Definition Allanite is a rare black or brown mineral consisting of the hydrated silicate of calcium, aluminium, iron, cerium, lanthanum, and other rare earth minerals. It occurs in granites and other igneous rocks. It has the general formula A2M3Si3O12[OH] where the A sites can contain l.....

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Tanzanite

Tanzanite

Tanzanite Definition Tanzanite is the violet to blue form of the mineral zoisite.  It is a calcium alumina hydroxy silicate. The gemstone was discovered by Manuel d’Souza in the Mirerani Hills of Manyara Region in Northern Tanzania in 1967, near the city of Arusha and Mount Kilimanjaro. Ta.....

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Zoisite

Zoisite

Zoisite Definition Zoisite is a grayish or whitish mineral occurring in orthorhombic, prismatic crystals, also in columnar masses. It is a silicate of alumina and lime, and is allied to epidote. Its chemical formula is Ca2Al3(SiO4)(Si2O7)O(OH). The most important and well-known is Tanzanite, a se.....

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Epidote

Epidote

Epidote Definition Epidote is a yellowish-green or blackish-green monoclinic mineral. Epidote occurs as formless grains or as prism-shaped crystals, and is found in limestones that have undergone slight metamorphism or in igneous rocks. Its chemical formula: Ca2(Al, Fe)3(SiO4)3OH. The finest and .....

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