Stephanite
Current inventory:  0 gems
 

  
Stephanite is named in honor of the Archduke Victor Stephan (1817–1867), former Mining Director of Austria.

Discovered in 1845;   IMA status:  Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Ag₅SbS₄

Silver Antimony Sulfide

Molecular Weight:

789.36 gm

Composition:

Silver

68.33 %

Ag

Antimony

15.42 %

Sb

Sulfur

16.25 %

S

Oxygen

45.99 %

O

100.00 %

Classification

Mineral Classification:

Sulfides

Strunz 8th Ed. ID:

2/E.06-10

Nickel-Strunz 10th Ed. ID:

2.GB.10

2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
G : Sulfarsenites, sulfantimonites, sulfbismuthites
B : Neso-sulfarsenites, etc. with additional S

Related to:

Stephanite Series

Varieties:

None

Synonyms:

Argento mineralisatum nigrum, Black Silver, Brittle Silver Ore, Goldschmidtine, Melane-glance, Melanglance, Psaturose, Röschwächs, Schwarzgülden (of Wallerius)

Crystal Data

Crystallography:

Orthorhombic - Pyramidal

Crystal Habit:

Crystals short prismatic to tabular [001], to 6 cm, also elongated along [100], with {110} striated parallel to [114]; massive, compact and disseminated.

Twinning:

On {110}, commonly repeated to form pseudohexagonal groups; less common on {130}, {100} and {010}, with composition plane {001}.

Physical Properties

Cleavage:

Imperfect on {010} and {021}

Fracture:

Sub-Conchoidal

Tenacity:

Brittle

Moh's Hardness:

2.0 - 2.5

Density:

6.26 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Iron-Black; in polished section, pale Gray

Transparency:

Opaque

Luster:

Metallic

Refractive Index:

R1–R2: (400) 32.0–33.0, (420) 32.1–33.2, (440) 32.2–33.4, (460) 31.5–33.2, (480) 30.7–32.6, (500) 30.0–32.0, (520) 29.0–31.3, (540) 28.4–30.6, (560) 28.0–30.2, (580) 27.6–29.8, (600) 27.5–29.6, (620) 27.6–29.6, (640) 27.8–29.5, (660) 28.0–29.2, (680) 28.5–28.7, (700) 28.2–28.2

Birefringence:

0.00

Dispersion:

n/a

Pleochroism:

Very Weak; white to pale pink

Anisotrophism:

Strong; in vivid colors

Occurances

Geological Setting:

A late-stage mineral in hydrothermal silver deposits.

Common Associations:

Proustite, Acanthite, Silver, Tetrahedrite, Galena, Sphalerite, Pyrite

Common Impurities:

As, Cu, Fe

Type Locality:

Freiberg District, Erzgebirge, Saxony, Germany

Year Discovered:

1845

View mineral photos:

Stephanite Mineral Photos and Locations

More Information

Mindat.org 
Webmineral.com

Stephanite is a somewhat rare silver bearing mineral. It is not a well known ore of silver but is a locally important ore in some mines. It is rarely available as a faceted gem and is for collectors of rare oddities, Black Gems or Metallic Gems. Stephanite typically forms as nicely shaped crystals that are tabular to short prismatic.

Stephanite is available from many silver mining localities, typically in small amounts, and only rarely in fine specimens. In Germany, at the Type Locality of Freiberg, Schneeberg, and Marienberg, Saxony; and as exceptional crystals from St. Andreasberg, Harz Mountains. In Slovakia, at Banská Hodrusa and from Banská Stiavnica (Schemnitz). In the Czech Republic, at Jáchymov (Joachimsthal), Príbram, and Trebsko. In Italy, fine twins from Monte Narba, near Sarrabus, Sardinia. In England, as twinned crystals from Wheal Boys, St. Endellion, Cornwall. At Espedalen, Norway. From Azegour, Morocco. At Altyn-Topkan, Tadjikistan. In Canada, in the Cobalt district, Ontario; at United Keno Hill Mines, and fine examples from the Husky mine, Elsa, Yukon Territory. In the USA, in Nevada, as an important ore mineral in the Comstock Lode, Virginia City, Storey County In Mexico, large crystals from Arizpe, Sonora; at Guanajuato; from Fresnillo, Zacatecas. At Chañarcillo, south of Copiapó, Atacama, Chile. In Bolivia, from Colquechaca, Potosí. At San Cristobal, Peru. From Broken Hill, New South Wales, Australia.
 

  
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