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CategorySulfide mineral
Thiospinel group
Spinel structural group
(repeating unit)
Strunz classification2.DA.05
Crystal systemCubic
Crystal classHexoctahedral (m3m)
H–M Symbol: (4/m 3 2/m)
Space groupFd3m
Unit cella = 9.520 Å; Z = 8
ColorSteel gray, creamy white in polished section
Crystal habitMinute subhedral to euhedral crystals typically enclosed within other sulfide minerals
Mohs scale hardness5
Specific gravity4.76 calculated
Polish lusterGood polish with moderate reflectivity
Optical propertiesIsotropic

Fletcherite is a rare thiospinel sulfide mineral with formula Cu(Ni,Co)2S4. It is an opaque metallic steel gray mineral which crystallizes in the cubic crystal system. It is a member of the linnaeite group.

It was first described in 1977 for an occurrence in the Fletcher Mine, Viburnum Trend (New Lead Belt), near Centerville, Reynolds County, Missouri.[2][1]

It occurs as a dissemination within copper sulfide minerals in mineralization replacing dolomite at the type locality in the Fletcher mine where it is associated with vaesite, pyrite, covellite, chalcopyrite, bornite and digenite. In an occurrence in Kalgoorlie, Australia it is found in black slate associated with pyrrhotite.[1]


  1. ^ a b c Handbook of Mineralogy
  2. ^ a b Mindat
  3. ^ Webmineral data
  4. ^ Craig, J. R.; Carpenter, A. B. (1 May 1977). "Fletcherite, Cu(Ni,Co)2S4, a new thiospinel from the Viburnum Trend (New Lead Belt), Missouri". Economic Geology. 72 (3): 480–486. doi:10.2113/gsecongeo.72.3.480.