Tetrahedrite
Current inventory:  0 gems
 

  
Tetrahedrite's name is derived from the common tetrahedral form of its crystals.

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

Chemistry

Chemical Formula:

Cu₉Fe²⁺₃Sb₄S₁₃

Copper Iron Antimony Sulfide

Molecular Weight:

1643.31 gm

Composition:

Iron

10.20 %

Fe

Copper

34.80 %

Cu

Antimony

29.64 %

Sb

Sulphur

25.37 %

O

100.00 %

Classification

Mineral Classification:

Sulfides

Strunz 8th Ed. ID:

2/C.11-40

Nickel-Strunz 10th Ed. ID:

2.GB.05

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:

Tetrahedrite Group. Tennantite-Tetrahedrite Series. Freibergite-Tetrahedrite Series.

Varieties:

Apthonite, Argentian Tetrahedrite, Argentiferous Auriferous Tetrahedrite, Arsenical Tetrahedrite, Bismuthian Tetrahedrite, Coppite, Frigidite, Kobaltfahlerz, Malinowskit, Mercurian Tetrahedrite, Stylotypite, Zincian Tetrahedrite

Synonyms:

Aftonite, Aphothonite, Clinohedrite (of Breithaupt), Falkenhaynite, Fieldite, Nepaulite, Panabase, Spiessglanzerz, Studerite

Crystal Data

Crystallography:

Isometric - Hextetrahedral

Crystal Habit:

Crystals are tetrahedral, to 15 cm; common as groups of parallel crystals; massive, coarse or fine and granular to compact.

Twinning:

On {111} around [111] as twin axis; contact and penetration twins, commonly repeated.

Physical Properties

Cleavage:

None

Fracture:

Sub-Conchoidal

Tenacity:

Somewhat Brittle

Moh's Hardness:

3.0 - 4.5

Density:

4.97 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Flint-Gray to iron-Black to dull Black, cherry-Red in transmitted light; in polished section, Gray inclining to olive-Brown.

Transparency:

Opaque, except in very thin fragments.

Luster:

Metallic

Refractive Index:

2.72  Isotropic

Birefringence:

0.00  (Isotropic)

Dispersion:

None

Pleochroism:

None

Other:

Color in reflected light: Gray to olive Brown

Occurances

Geological Setting:

Typically in hydrothermal veins or contact metamorphic deposits of low to medium temperature of formation.

Common Associations:

Chalcopyrite, Galena, Sphalerite, Pyrite, Bornite, Acanthite, Calcite, Dolomite, Siderite, Barite, Fluorite, Quartz.

Common Impurities:

Ag, Pb, Zn, Fe, As

Type Locality:

Freiberg, Freiberg District, Erzgebirge, Saxony, Germany

Year Discovered:

1845

View mineral photos:

Tetrahedrite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Tetrahedrite is a copper antimony sulfosalt mineral that is named for its common crystal form, the tetrahedron.It is one of the most common of the sulfosalts and its tpypical tetrahedron crystals can be quite attractive and interesting as mineral specimens. Tetrahedrite often contains a certain percentage of silver as an impurity and is mined as a minor ore. Some iron, zinc and/or silver is always present in Tetrahedrite, up to approximately 15%, as impurities. Tetrahedrite forms a solid solution series with the rather rare mineral Tennantite (Copper Arsenic Sulfide). The two share the same crystal structure but they differ in the percentage of arsenic versus antimony. Antimony rich specimens are Tetrahedrite while arsenic rich specimens are Tennantite. Tetrahedrite is flint-gray to iron-black and is included in my Black Gems page. Although fairly common as a mineral specimen, it is rarely available as a faceted gem although gems are very attractive with their metallic luster.

There are many locations for Tetrahedrite worldwide but I am only listing a few localities which have produced well-crystallized material. In Germany, from Freiberg, Saxony, and in the Harz Mountains, at Clausthal and Horhausen. From near Brixlegg, Tirol, Austria. At Botés, near Zlatna, and Cavnic (Kapnikbánya), Romania. In France, at Irazein, Ariège, France, a few exceptionally large crystals, and from Sainte-Marie-aux-Mines, Haut-Rhin. In Cornwall, England, at the Herodsfoot mine. In Algeria, from near Tenés and Mouzaía. In Bolivia, at the San José mine, Oruro. In Peru, from Casapalca, Junin, in the Huallanca and Quiruvilca districts, and at many other places. From the Noche Buena mine, Mazapil, and at the El Cobre mine, Concepción del Oro, Zacatecas, Mexico. In the USA, in the Daly-Judge and other mines, Park City district, Summit County, Utah. From the Nanisivik mine, Baffin Island, Nunavut, Canada.
 

  
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