Enargite

Enargite
General
CategorySulfosalt mineral
Formula
(repeating unit)
Cu3AsS4
IMA symbolEng[1]
Strunz classification2.KA.05
Crystal systemOrthorhombic
Crystal classPyramidal (mm2)
H-M symbol: (mm2)
Space groupPmn21
Unit cella = 7.407(1), b = 6.436(1)
c = 6.154(1) [Å]; Z = 2
Identification
ColorGrayish black to iron black; gray to pale pink-brown, deep red internal reflections in polished section
Crystal habitTabular to prismatic crystals, striated parallel to {001}; massive
TwinningTwin plane {320} common, rarely as interpenetrating pseudohexagonal trillings
CleavagePerfect on {110}, distinct {100} and {010}
FractureUneven
TenacityBrittle
Mohs scale hardness3
LusterMetallic to dull
StreakBlack
DiaphaneityOpaque
Specific gravity4.4 to 4.5
References[2][3][4]

Enargite is a copper arsenic sulfosalt mineral with formula Cu3AsS4. It takes its name from the Greek word enarge, "distinct". Enargite is a steel gray, blackish gray, to violet black mineral with metallic luster. It forms slender orthorhombic prisms as well as massive aggregates. It has a hardness of 3 and a specific gravity of 4.45.

Enargite is dimorph of the tetragonal luzonite.[2]

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b http://www.mindat.org/min-1380.html Mindat
  3. ^ http://webmineral.com/data/Enargite.shtml Webmineral
  4. ^ Handbook of Mineralogy