{{Other uses|Telluric silver}} {{Short description|Telluric silver mineral}} {{Infobox mineral | name = Empressite | category = Telluride mineral | boxwidth = | boxbgcolor = | image = Empressite-583052.jpg | imagesize = 260px | caption = Empressite from Joe mine, Tombstone district | formula = AgTe | IMAsymbol = Eps<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}</ref> | molweight = | strunz = 2.CB.80 | system = Orthorhombic | class = Dipyramidal (mmm) <br/>H-M symbol: (2/m 2/m 2/m) | symmetry = ''Pmnb'' | color = Pale bronze | habit = Granular masses | twinning = | cleavage = None | fracture = Uneven to subconchoidal | tenacity = Brittle | mohs = 3.5 | luster = Metallic | streak = Gray-black to black | polish = | refractive = | opticalprop = Opaque | birefringence = | dispersion = | pleochroism = Very strong, in gray to creamy white | fluorescence= | absorption = | gravity = 7.6 | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Opaque | other = | references = <ref>http://rruff.geo.arizona.edu/doclib/hom/empressite.pdf Handbook of Mineralogy</ref><ref>http://www.webmineral.com/data/Empressite.shtml Webmineral</ref><ref name=Mindat>http://www.mindat.org/min-1379.html Mindat</ref> }} '''Empressite''' or ''tellursilberblende'' is a mineral form of silver telluride, AgTe. It is a rare, grey, orthorhombic mineral with which can form compact masses, rarely as bipyramidal crystals.
Recent crystallographic analysis<ref>L. Bindi ''et al.'', American Mineralogist, '''89''', 1043 (2004)</ref> has confirmed that empressite is a distinct mineral with orthorhombic crystal structure, different from the hexagonal Ag<sub>5−x</sub>Te<sub>3</sub> with which empressite has been commonly confused in mineralogy literature. At the same time, empressite does not appear on the equilibrium Ag-Te phase diagram,<ref>Karakaya, I., Thompson, W.T.: J. Phase Equilibria '''12''', 56 (1991).</ref> and therefore it is only metastable at ambient conditions. Given infinite time, it would phase separate into pure Ag<sub>5</sub>Te<sub>3</sub> and pure Te.
The name empressite comes from the location of its discovery – the Empress Josephine mine, Saguache County, Colorado, US. It was first described in 1914.<ref name=Mindat/>
==References== {{reflist}}
Category:Silver minerals Category:Telluride minerals Category:Orthorhombic minerals Category:Minerals in space group 62 Category:Minerals described in 1914 Category:Blendes
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