Djerfisherite
Djerfisherite found in Russia
General
CategorySulfide mineral
Formula
(repeating unit)		See text
IMA symbolDjr[1]
Strunz classification2.FC.05
Crystal systemCubic
Crystal classHexoctahedral (m3m)
H-M symbol: (4/m 3 2/m)
Space groupPm3m
Unit cella = 10.465 Å; Z = 1
Identification
ColorGreenish yellow, khaki to olive drab
Crystal habitRounded grains
Mohs scale hardness3.5
LusterSubmetallic
DiaphaneityOpaque
Optical propertiesIsotropic
References[2][3][4]

Djerfisherite is an alkali copper–iron sulfide mineral and a member of the djerfisherite group.

The chemical composition is somewhat variable. A Russian study from 1979 on djerfisherite from the Kola Peninsula found the formula K
6Na(Fe,Cu)
24S
26Cl, but a study in 2007 of a samples from Siberia found no detectable sodium and states that the formula K
6(Fe,Cu,Ni)
25S
26Cl is considered the most appropriate.[5] Both crystallographic studies have 58 atoms per unit cell. Sulfur atoms are in three nonequivalent locations, containing 12, 6, and 8 atoms per unit cell. The later study put a copper atom where the earlier study put a sodium atom.[6] More information on the structure and other questions is available,[5] as well as 3-D models.[2]

The Webmineral "Mineralogy Database" site gives the "chemical formula" as K
6Na(Fe2+
,Cu,Ni)
25S
26Cl, apparently in error, and an "empirical formula" as K
6NaFe2+
19Cu
4NiS
26Cl.[4]

Its type locality is the Kota-Kota meteorite (Marimba meteorite), Malawi. It was first described in 1966 and named after professor Daniel Jerome Fisher (1896–1988), University of Chicago.[2] It has been reported from meteorites, copper-nickel hydrothermal deposits, skarn, pegmatite, kimberlites and alkalic intrusive complexes. Associated minerals include kamacite, troilite, schreibersite, clinoenstatite, tridymite, cristobalite, daubreelite, graphite, roedderite, alabandite, talnakhite, pentlandite, chalcopyrite, magnetite, valleriite, sphalerite and platinum minerals.[3]

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. 1 2 3 Mindat.org - Djerfisherite
  3. 1 2 Djerfisherite in the Handbook of Mineralogy
  4. 1 2 Djerfisherite data on Webmineral
  5. 1 2 Federica Zaccarini; et al. (2007). "Djerfisherite in the Guli dunite complex, polar Siberia: a primary or metasomatic phase?" (PDF). The Canadian Mineralogist. 45 (5): 1201–1211. doi:10.2113/gscanmin.45.5.1201. S2CID 129976188.
  6. ↑ "Djerfisherite". American Mineralogist Crystal Structure Database. University of Arizona.


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