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. | fracture = | tenacity = Sectile | mohs = 1.5 - 2.5 | luster = Subadamantine, pearly on cleavages | streak = Pale red to pink | diaphaneity = Transparent to translucent | gravity = 3.06 | density = | polish = | opticalprop = Biaxial (+) | refractive = nα = 1.626 - 1.629 nβ = 1.662 - 1.663 nγ = 1.699 - 1.701 | birefringence = δ = 0.073 | pleochroism = Visible: X = pale pinkish to pale rose; Y = pale violet to pale violet-rose; Z = deep red | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence= | absorption = | melt = | fusibility = | diagnostic = | solubility = | other = | alteration = | references = 〔http://rruff.geo.arizona.edu/doclib/hom/erythrite.pdf Handbook of Mineralogy〕〔http://www.mindat.org/min-1407.html Mindat.org〕〔http://webmineral.com/data/Erythrite.shtml Webmineral data〕 }} Erythrite or red cobalt is a secondary hydrated cobalt arsenate mineral with the formula (Co3(AsO4)2·8H2O). Erythrite and annabergite (Ni3(AsO4)2·8H2O) (nickel arsenate) form a complete series with the general formula (Co,Ni)3(AsO4)2·8H2O. Erythrite crystallizes in the monoclinic system and forms prismatic crystals. The color is crimson to pink and occurs as a secondary coating known as ''cobalt bloom'' on cobalt arsenide minerals. Well-formed crystals are rare, with most of the mineral manifesting in crusts or small reniform aggregates. Erythrite was first described in 1832 for an occurrence in Grube Daniel, Schneeberg, Saxony,〔 and takes its name from the Greek έρυθρος (''erythros''), meaning red.〔 Historically, erythrite itself has not been an economically important mineral, but the prospector may use it as a guide to associated cobalt and native silver. Erythrite occurs as a secondary mineral in the oxide zone of Co–Ni–As bearing mineral deposits. It occurs in association with cobaltite, skutterudite, symplesite, roselite-beta, scorodite, pharmacosiderite, adamite, morenosite, retgersite, and malachite.〔 Notable localities are Cobalt, Ontario; Schneeberg, Saxony, Germany; Joachimsthal, Czech Republic; Cornwall, England; Bou Azzer, Morocco; the Blackbird mine, Lemhi County, Idaho; Sara Alicia mine, near Alamos, Sonora, Mexico; Mt. Cobalt, Queensland and the Dome Rock copper mine, Mingary, South Australia.〔 ==Other varieties== The nickel variety, annabergite, occurs as a light green ''nickel bloom'' on nickel arsenides. In addition iron, magnesium and zinc can also substitute for the cobalt position, creating three other minerals: parasymplesite (Fe), hörnesite (Mg) and kottigite (Zn). 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「erythrite」の詳細全文を読む スポンサード リンク
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