stephanite

{{infobox mineral | name = Stephanite | category = Sulfosalt mineral |image = Stephanite-oldeuro-119a.jpg | caption = | formula = Ag5SbS4 | IMAsymbol = Sph | molweight = | strunz = 2.GB.10 | dana = 03.02.04.01 | system = Orthorhombic | class = Pyramidal (mm2) H-M symbol: (mm2) | symmetry = Cmc21 | colour = Lead grey to black | color = | habit = Tabular, pseudo-hexagonal crystals; massive | twinning = Common on [110] repeated, forms pseudohexagonal groupings | cleavage = Imperfect on {010}, poor on {021} | fracture = Subconchoidal | tenacity = Brittle | mohs = 2.0–2.5 | lustre = Metallic | streak = Iron black | diaphaneity = Opaque | gravity = 6.26 | density = | polish = | opticalprop = Anisotropic in polished section | refractive = | birefringence = | pleochroism = Very weak – white to pale pink | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence= | absorption = | melt = | fusibility = | diagnostic = | solubility = | other = | alteration = | references = }} Stephanite is a silver antimony sulfosalt mineral with formula: Ag5SbS4. It is composed of 68.8% silver, and sometimes is of importance as an ore of this metal.

==History== Under the name Schwarzerz it was mentioned by Georgius Agricola in 1546, and it has been variously known as "black silver ore" (German Schwarzgultigerz), brittle silver-ore (Sprödglanzerz), etc. The name stephanite was proposed by W Haidinger in 1845 in honour of the Archduke of Austria Stephan Franz Victor of Habsburg-Lorena (1817–1867). French authors use F. S. Beudant's name psaturose (from the Greek ψαθυρός, fragile).