Fletcherite

Cu(Ni,Co)2S4IMA symbolFtc[1]Strunz classification2.DA.05Crystal systemCubicCrystal classHexoctahedral (m3m)
H–M Symbol: (4/m 3 2/m)Space groupFd3mUnit cella = 9.520 Å; Z = 8IdentificationColorSteel gray, creamy white in polished sectionCrystal habitMinute subhedral to euhedral crystals typically enclosed within other sulfide mineralsMohs scale hardness5LusterMetallicDiaphaneityOpaqueSpecific gravity4.76 calculatedPolish lusterGood polish with moderate reflectivityOptical propertiesIsotropicReferences[2][3][4][5]

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.[3][2]

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.[2]

References

  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 c Handbook of Mineralogy
  3. ^ a b Mindat
  4. ^ Webmineral data
  5. ^ 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.


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