Provenite

About Enargite

Cu₃AsS₄

A copper arsenic sulfosalt that forms black, metallic, strongly striated prismatic or tabular crystals with a perfect prismatic cleavage. Widespread and locally an important copper ore, but well-formed crystals are known from relatively few localities.

Show 12 localities on the map

Photos of Enargite

Cluster of striated, jet-black enargite prisms from Butte, about 4.7 cm across.
Enargite · Butte Mining District
Cluster of striated, jet-black enargite prisms from Butte, about 4.7 cm across.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Small cluster of sharp, terminated enargite crystals from the Leonard Mine.
Enargite · Leonard Mine
Small cluster of sharp, terminated enargite crystals from the Leonard Mine.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Black striated enargite blades tipped with luzonite around lustrous pyrite, Pen-Shan ore body, Chinkuashih Mine.
Enargite · Chinkuashih Mine (Jinguashi)
Black striated enargite blades tipped with luzonite around lustrous pyrite, Pen-Shan ore body, Chinkuashih Mine.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Stacked, terminated enargite crystals from the Quiruvilca Mine.
Enargite · Quiruvilca
Stacked, terminated enargite crystals from the Quiruvilca Mine.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Cluster of lustrous dark gray enargite blades from the Julcani Mine.
Enargite · Julcani Mine
Cluster of lustrous dark gray enargite blades from the Julcani Mine.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Piece of enargite ore with a pocket of sharp enargite crystals from Cerro de Pasco.
Enargite · Cerro de Pasco
Piece of enargite ore with a pocket of sharp enargite crystals from Cerro de Pasco.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Tabular, striated gray-black enargite crystals on quartz from the Sweet Home Mine.
Enargite · Sweet Home Mine
Tabular, striated gray-black enargite crystals on quartz from the Sweet Home Mine.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Enargite with pyrite from the Badger State Mine, Butte, in the South Dakota School of Mines museum collection.
Enargite · Badger State Mine
Enargite with pyrite from the Badger State Mine, Butte, in the South Dakota School of Mines museum collection.
Photo: James St. John · CC BY 2.0 · Source

Where Enargite is found (12)

Namibia

Peru

Taiwan

United States

Enargite on the same specimen with other minerals

Same specimen Enargite with Sphalerite at Butte Mining District

2 specimen photo(s) from this locality show sphalerite with enargite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Quartz with Enargite at Butte Mining District

1 specimen photo(s) from this locality show enargite with quartz together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Quartz with Enargite at Leonard Mine

1 specimen photo(s) from this locality show enargite with quartz together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Pyrite with Enargite at Leonard Mine

1 specimen photo(s) from this locality show enargite with pyrite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Pyrite with Enargite at Kelley Mine

1 specimen photo(s) from this locality show enargite with pyrite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Pyrite with Enargite at Stewart Mine

1 specimen photo(s) from this locality show enargite with pyrite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Pyrite with Enargite at Chinkuashih Mine (Jinguashi)

2 specimen photo(s) from this locality show enargite with pyrite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Identity

Strunz
2.KA.05 · 2 Sulfides and sulfosalts
IMA status
Grandfathered
Name origin
From the Greek word for 'distinct', referring to its distinct cleavage.
Elements
Cu, As, S

Physical properties

Color
Grayish black to iron-black; gray to pale pink-brown in polished section
Streak
Grayish black
Luster
Metallic luster
Transparency
Opaque
Mohs hardness
3
Density
4.4–4.45 g/cm³
Cleavage / fracture
Perfect cleavage on {110}, distinct on {100} and {010}, indistinct on {001}; fracture uneven; brittle
Magnetism / fluorescence
Nonmagnetic; non-fluorescent

Crystallography

Crystal system
Orthorhombic
Space group
Pmn21
Structure
Orthorhombic, point group mm2; a = 7.407, b = 6.436, c = 6.154 Å, Z = 2. Stacking disorder and polytypism with luzonite are described.
Typical habit
Tabular on {001} or prismatic along [001], with the prism zone deeply striated parallel to [001]; crystals up to 15 cm; also massive
Twinning
Twin plane {320} common; rarely interpenetrating pseudohexagonal trillings
Optical data
Opaque; in reflected light gray to pale pink-brown, weakly pleochroic and very strongly anisotropic (dark violet-red or olive-green tints); deep red internal reflections may be seen

Formation and use

Formation
Hydrothermal veins formed at medium temperatures; also a late-stage mineral in low-temperature deposits. Associated with pyrite, sphalerite, galena, bornite, tetrahedrite-tennantite, chalcocite, covellite, barite and quartz.
Uses
Ore of copper where abundant; collector specimens.

Related minerals

Related minerals
Luzonitepetrukitestibioenargite
Polymorphs
Luzonite

Sources

  1. SRC-642 · Book
    Handbook of Mineralogy - EnargiteAnthony, J.W.; Bideaux, R.A.; Bladh, K.W.; Nichols, M.C. · 2005 · Mineral Data Publishing / Mineralogical Society of America
  2. SRC-643 · Database
    Enargite Mineral DataBarthelmy, D. · Webmineral.com

Draft data from the Provenite workbook. Check entries against the cited sources before relying on them. Photos are open-licence images from Wikimedia Commons; the author and licence are given with each photo.