Cuprokalininite

Cu(Cr3+Cr4+)S4
IMA status
  • Approved
IMA symbol
Ckal
IMA approved
2010
Also known as
  • Cuprokalininiet
  • IMA2010-008

Where it forms, where it's found

Geological setting

In a Cr-V-bearing quartz-diopside metamorphic rock.

Type locality
Pereval marble quarry
  1. Slyudyanka
  2. Russia

51.6201°, 103.6334°

2recorded occurrences
Source · OpenStreetMap

Physical

Hardness
123456789104.5 – 5/ 10 MOHS
  1. 1Talc
  2. 2Gypsum
  3. 3Calcite
  4. 4Fluorite
  5. 5Apatite
  6. 6Orthoclase
  7. 7Quartz
  8. 8Topaz
  9. 9Corundum
  10. 10Diamond
Colour
Black

with a weak dark bronze tint

Streak
Black
Tenacity
very brittle
Cleavage
None Observed
Fracture
Irregular/Uneven
Density
4.16 g/cm³

Optical

Optical colour
Pale cream
Internal reflections
None observed
Tropism
Isotropic
Reflectance R%
(34.30) 400, (34.10) 420, (33.90) 440, (33.70) 460, (33.50) 480, (33.20) 500, (33.00) 520, (32.80) 540, (32.50) 560, (32.20) 580, (31.90) 600, (31.60) 620, (31.20) 640, (30.90) 660, (30.60) 680, (30.40) 700
Reflected-light panel
32.5 %isotropic · single curve
Specimen sRGB 202, 143, 81
White reference100 % reflector under same lamp
Reflected colour
Pale cream
Internal reflections
None observed

Crystallography

Crystal system
Isometric
Space group
#222
Cell parameters
a = 9.814(2) Å
Unit cell volume
945.2 ų
Z
8
Morphology

Dominant forms are (111) and (100) with distinct growth steps.

Twinning

Polysynthetic twins on (111) are typical. Occasionally, simple twinning by the spinel law is identified.

Type-locality form

Euhedral octahedral or cubo-octahedral microcrystals up to 0.2 mm in size.

Crystal structure

Chemical composition

Constituent elements
Mass composition breakdown
ElementAtoms At. mass g/mol Mass g/molMass share
16SSulfurSulfur432.060128.240
43.36%
24CrChromiumChromium251.996103.992
35.16%
29CuCopperCopper163.54663.546
21.48%
Total295.778100.00%

Mass share = atoms × atomic mass ÷ molar mass × 100

From IMA formula

Impurities
  • V
  • Fe
  • Zn

Synonyms

  • Cuprokalininiet
  • IMA2010-008

In other languages

German
Cuprokalininit · IMA 2010-008
Italian
cuprokalininite

Classification

Strunz
10th ed.

2.DA.05

  • 2Sulfides and SulfosaltsClass
  • 2.DMetal Sulfides, M: S = 3 :4 and 2:3Division
  • 2.DAM:S = 3:4Group
  • 2.DA.05CuprokalininiteSpecies
Dana
8th ed.

02.10.01.20

  • 02SulfidesClass
  • 02.10AmBnXp, with (m+n):p = 3:4Type
  • 02.10.01Linnaeite Group (Isometric: Fd3m)Group
  • 02.10.01.20CuprokalininiteSpecies

Group, growth & confusion

Literature, links & citation

Citations
  1. 2010Reznitsky, L.Z., Sklyarov, E.V., Ushchapovskaya, Z.F., Suvorova, L.F., Polekhovsky, Yu.S., Dzerzanovsky, P., Barash, I.G. (2010) Cuprokalininite CuCr2S4 - the new sulfospinel from metamorphic rocks of Sludyanka Complex (South Baikal Region). [Zapiski Rossiyskogo Mineralogicheskogo Obshchestva], 139 (6) 39-49
  2. 2010Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2010) New minerals and nomenclature modifications approved in 2010. CNMNC Newsletter No 3. Mineralogical Magazine, 74 (3) 577-579 doi:10.1180/s0026461x00054979 DOI: 10.1180/s0026461x00054979
  3. 2011Reznitsky, L. Z., Sklyarov, E. V., Ushchapovskaya, Z. F., Suvorova, L. F., Polekhovsky, Yu. S., Dzerzanovsky, P., Barash, I. G. (2011) Cuprokalininite, CuCr2S4, a new sulfospinel from metamorphic rocks of the Sludyanka Complex, South Baikal region. Geology of Ore Deposits, 53 (8) 758-766 doi:10.1134/s1075701511080137 DOI: 10.1134/s1075701511080137
  4. 2014(2014) Cuprokalininite. Handbook of Mineralogy. Mineralogical Society of America
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Cuprokalininite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/cuprokalininite-40142},
  note      = {Accessed 2026-05-11}
}