Magnesiocopiapite

MgFe3+4(SO4)6(OH)2 · 20H2O
IMA status
  • Approved
  • Grandfathered
IMA symbol
Mcpi
Discovered
1938
Also known as
  • Magnesiocopiapiet

Where it forms, where it's found

Type locality
Blythe
  1. Riverside County
  2. California
  3. USA

33.6103°, -114.5956°

62recorded occurrences
Source · OpenStreetMap

Varieties

Physical

Hardness
123456789102.5 – 3/ 10 MOHS
  1. 1Talc
  2. 2Gypsum
  3. 3Calcite
  4. 4Fluorite
  5. 5Apatite
  6. 6Orthoclase
  7. 7Quartz
  8. 8Topaz
  9. 9Corundum
  10. 10Diamond

Crystallography

Crystal system
Triclinic
Space group
#2
Cell parameters
a = 7.3451(4) Å · b = 18.794(1) Å · c = 7.3891(4) Å
Cell angles
α = 91.369(5) ° · β = 102.169(4) ° · γ = 98.831(4) °
Ratio a:b:c
1 : 2.559 : 1.006
Unit cell volume
983.6 ų
Comment

Synthetic (Majzlan & Michallik, 2007).

Crystal structure

Chemical composition

Constituent elements
Mass composition breakdown
ElementAtoms At. mass g/mol Mass g/molMass share
8OOxygenOxygen4615.999735.954
60.41%
26FeIronIron455.845223.380
18.33%
16SSulfurSulfur632.060192.360
15.79%
1HHydrogenHydrogen421.00842.336
3.47%
12MgMagnesiumMagnesium124.30524.305
2.00%
Total1218.335100.00%

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

From IMA formula

Synonyms

  • Magnesiocopiapiet

In other languages

German
Magnesiocopiapit
Italian
Magnesiocopiapite

Classification

Strunz
10th ed.

7.DB.35

  • 7SulfatesClass
  • 7.DSulfates (selenates, etc.) with additional anions, with H2ODivision
  • 7.DBWith only medium-sized cations; insular octahedra and finite unitsGroup
  • 7.DB.35MagnesiocopiapiteSpecies
Dana
8th ed.

31.10.05.02

  • 31Hydrated Sulfates Containing Hydroxyl or HalogenClass
  • 31.10MiscellaneousType
  • 31.10.05Copiapite GroupGroup
  • 31.10.05.02MagnesiocopiapiteSpecies

Group, growth & confusion

Often grow together
1 mineral

Literature, links & citation

Citations
  1. 1938Berry, L.G. (1938) Composition and optics of copiapite. in Nineteenth Annual Meeting, Mineralogical Society of America, Waldorf-Astoria Hotel, New York City, December 28-30, 1938, Program, abstracts, and time schedule for presentation of papers. American Mineralogist: 23(12)pt2: 3-3.
  2. 1939(1939) American Mineralogist : 24: 182.
  3. 1947Berry, L.G. (1947) Composition and optics of copiapite. University of Toronto Studies: VI. Geological Series, 51, 21-34.
  4. 1951Palache, Charles; Berman, Harry; Frondel, Clifford (1951) The System of Mineralogy (7th ed.) Vol. 2 - Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. John Wiley and Sons.
  5. 1985Bayliss, P., Atencio, D. (1985) X-ray powder-diffraction data and cell parameters for copiapite-group minerals. The Canadian Mineralogist, 23 (1) 53-56
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Magnesiocopiapite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/magnesiocopiapite-2486},
  note      = {Accessed 2026-05-11}
}