Stephanite
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205280563
2008-04-13T06:31:37Z
Tavilis
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name and time
[[Image:Mineraly.sk - stefanit.jpg|right|thumb|a sample of stephanite]]
'''Stephanite''' is a [[silver]] [[antimony]] [[sulfide]] [[mineral]] with formula: [[silver|Ag]]<sub>5</sub>[[antimony|Sb]][[sulfur|S]]<sub>4</sub> It is composed of 68.8% [[silver]], and sometimes is of importance as an ore of this metal.
Under the name Schwarzerz it was mentioned by [[Georgius Agricola]] in [[1546]], and it has been variously known as "black silver ore" ([[German language|German]] ''Schwarzgultigerz''), brittle silver-ore (''Sprodglanzerz''), etc. The name stephanite was proposed by [[Wilhelm Karl Ritter von Haidinger|W Haidinger]] in [[1845]] in honour of the [[Stephan, Archduke of Austria|archduke Stephan Franz Victor of Habsburg-Lorena]] (1817-1867); French authors use [[François Sulpice Beudant|F. S. Beudant]]'s name psalurose (from the [[Greek language|Greek]] ''ψαλoυρος'', fragile).
It frequently occurs as well-formed crystals, which are [[orthorhombic]] and occasionally show indications of [[hemimorphism]]: they have the form of six-sided [[prism (geometry)|prism]]s or flat tables terminated by large basal planes and often modified at the edges by numerous pyramid-planes. [[Crystal twinning|Twinning]] on the prism-planes is of frequent occurrence, giving rise to pseudo-hexagonal groups like those of [[aragonite]]. The colour is iron-black, and the lustre metallic and brilliant; on exposure to light, however, the crystals soon become dull.
The mineral has a [[Mohs hardness]] of 2-2.5 and is very brittle; the [[specific gravity]] is 6.3. Stephanite occurs with other ores of silver in metalliferous veins. Localities which have yielded good crystallized specimens are Freiberg and Gersdorf near Rosswein in [[Saxony]], Chanarcillo in [[Chile]], and exceptionally [[Cornwall]]. In the Comstock lode in [[Nevada]] massive stephanite and argentite are important ores of silver.
==See also==
* [[Black silver art]]
* [[List of minerals]]
* [[List of minerals named after people]]
==References==
*{{1911}}
[[Category:Silver minerals]]
[[Category:Antimony minerals]]
[[Category:Sulfosalt minerals]]
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