Arakiite (IMA symbol: Ark[1]) is a rare mineral with the formula (Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As3+O3)(As5+O4)2(OH)23.[2] It is both arsenate and arsenite mineral, a combination that is rare in the world of minerals. Arakiite is stoichiometrically similar to hematolite. It is one of many rare minerals coming from the famous Långban manganese skarn deposit in Sweden. Other minerals bearing both arsenite and zinc include kraisslite and mcgovernite.[3]

Arakiite
General
CategoryMineral
Formula
(repeating unit)
(Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As3+O3)(As5+O4)2(OH)23
IMA symbolArk
Identification
ColorRed-brown to orange-brown
Mohs scale hardness3-4
LusterEarthy
StreakPale-brown, red-brown
DiaphaneityTranslucent, Opaque
Specific gravity3.41
Density3.41 g/cm3

The mineral crystallizes in the monoclinic crystal system in space group Cc.[4]

References

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  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. ^ Roberts, A.C., Grice, J.D., Cooper, M.A., Hawthorne, F.C., and Feinglos, M.N., 2000. A new Zn-bearing hematolite-like mineral from Långban, Värmland, Sweden. Mineralogical Record 31(3), 253-256
  3. ^ "Arakiite: Arakiite mineral information and data". Mindat.org. Retrieved 2016-03-04.
  4. ^ Cooper, M.A.; Hawthorne, F.C. (1999). "The effect of differences in coordination on ordering of polyvalent cations in close-packed structures: The crystal structure of arakiite and comparison with hematolite". The Canadian Mineralogist. 37: 1471–1482.