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Proustite is a sulfosalt mineral consisting of; silver sulfarsenide, Ag3AsS3, known also as light red silver or ruby silver ore, and an important source of the metal. It is closely allied to the corresponding sulfantimonide, pyrargyrite, from which it was distinguished by the chemical analyses of Joseph L. Proust (1754-1826) in 1804, after whom the mineral received its name. The prismatic crystals are often terminated by the scalenohedron and the obtuse rhombohedron, thus resembling calcite (dog-tooth-spar) in habit. The color is scarlet-vermilion and the lustre adamantine; crystals are transparent and very brilliant, but on exposure to light they soon become dull black and opaque. The streak is scarlet, the hardness 2.5, and the specific gravity 5.57. Proustite occurs in hydrothermal deposits as a phase in the oxidized and supergene zone. It is associated with other silver minerals and sulfides such as native silver, native arsenic, xanthoconite, stephanite, acanthite, tetrahedrite and chlorargyrite.〔 Magnificent groups of large crystals have been found at Chañarcillo in Chile; other localities which have yielded fine specimens are Freiberg and Marienberg in Saxony, Joachimsthal in Bohemia and Markirch in Alsace. File:Proustite (long prismatic crystal) - Chanarcillo, Copiapo Province, Atacama Region, Chile.jpg|Proustite (long prismatic crystal) - Chañarcillo, Copiapo Province, Chile. Specimen height is 4 cm. ==See also== *List of minerals *List of minerals named after people 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「proustite」の詳細全文を読む スポンサード リンク
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