Covellite

Covellite
General
CategorySulfide mineral
Formula
(repeating unit)
CuS (copper monosulfide)
IMA symbolCv[1]
Strunz classification2.CA.05a
Dana classification02.08.12.01
Crystal systemHexagonal
Crystal classDihexagonal dipyramidal (6/mmm)
H–M Symbol (6/m 2/m 2/m)
Space groupP63/mmc
Unit cella = 3.7938 Å, c = 16.341 Å; Z = 6
Identification
ColorIndigo-blue or darker, commonly highly iridescent, brass-yellow to deep red
Crystal habitThin platy hexagonal crystals and rosettes also massive to granular.
CleavagePerfect on {0001}
TenacityFlexible
Mohs scale hardness1.5–2
LusterSubmetallic, inclining to resinous to dull
StreakLead gray
DiaphaneityOpaque
Specific gravity4.6–4.8
Optical propertiesUniaxial (+)
Refractive indexnω = 1.450 nε = 2.620
PleochroismMarked, deep blue to pale blue
Fusibility2.5
Other characteristicsMicaceous cleavage
References[2][3][4]
Covellite (gray) replacing and embaying chalcopyrite (light), polished section from Horn Silver Mine, San Francisco Mining District, Utah. Enlarged to 210 diameters.

Covellite (also known as covelline) is a rare copper sulfide mineral with the formula CuS.[4] This indigo blue mineral is commonly a secondary mineral in limited abundance and although it is not an important ore of copper itself, it is well known to mineral collectors.[4]

The mineral is generally found in zones of secondary enrichment (supergene) of copper sulfide deposits. Commonly found as coatings on chalcocite, chalcopyrite, bornite, enargite, pyrite, and other sulfides, it often occurs as pseudomorphic replacements of other minerals.[5] The first records are from Mount Vesuvius, formally named in 1832 after N. Covelli.[4]

  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. ^ Handbook of Mineralogy
  3. ^ Webmineral data
  4. ^ a b c d Mindat.org
  5. ^ Q. Ashton Acton (2012). Chlorine Compounds-Advances in Research and Application. ScholarlyMedia LLC. ISBN 9781481600040. OCLC 1024280169.