Richelsdorfite

Ca2Cu5Sb5+(AsO4)4(OH)6Cl · 6H2O
IMA status
  • Approved
IMA symbol
Rdf
Discovered
1982
IMA approved
1982
Also known as
  • IMA1982-019
  • Richelsdorfiet

Where it forms, where it's found

Type locality
Wilhelm Mine
  1. Nentershausen
  2. Hersfeld-Rotenburg
  3. Kassel Region
  4. Hesse
  5. Germany

50.9963°, 9.9517°

56recorded occurrences
Source · OpenStreetMap

Safety & handling

Physical

Hardness
123456789102/ 10 MOHS
  1. 1Talc
  2. 2Gypsum
  3. 3Calcite
  4. 4Fluorite
  5. 5Apatite
  6. 6Orthoclase
  7. 7Quartz
  8. 8Topaz
  9. 9Corundum
  10. 10Diamond
Colour
Turquoise-blue

Optical

Optical type
Biaxial (-) · 2V measured = 10 – 15° · 2V calc = 20°
Refractive index
1.64 – 1.694
Surface relief
High
Principal indices
nα 1.64 · nβ 1.692 · nγ 1.694
Dispersion
relatively weak
Michel-Lévy diagramhighlighted lineδ = 0.0540
Attainable Michel-Lévy rangeΔ ∈ [0, t·δmax]540 nm1st order
Δ = 0Δmax
Thin-section mosaic70 grains · random 3D orientations
PPLpleochroism per grain
XPLindependent extinctions · rotate the stage
Interference simulatorsingle grain · PPL ↔ XPL
PPLpleochroism only · colour blends on rotation
XPLinterference colour · extinct every 90°
Retardation540 nm
Order1st order
XPL colour

Crystallography

Crystal system
Monoclinic
Space group
C2/m
Cell parameters
a = 14.08 Å · b = 14.21 Å · c = 13.49 Å
Cell angles
β = 101.06 °
Ratio a:b:c
1 : 1.009 : 0.958
Z
4
Crystal structure

Chemical composition

Constituent elements
Mass composition breakdown
ElementAtoms At. mass g/mol Mass g/molMass share
8OOxygenOxygen2815.999447.972
33.92%
29CuCopperCopper563.546317.730
24.05%
33AsArsenicArsenic474.922299.688
22.69%
51SbAntimonyAntimony1121.760121.760
9.22%
20CaCalciumCalcium240.07880.156
6.07%
17ClChlorineChlorine135.45035.450
2.68%
1HHydrogenHydrogen181.00818.144
1.37%
Total1320.900100.00%

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

From IMA formula

Synonyms

  • IMA1982-019
  • Richelsdorfiet

In other languages

German
IMA1982-019 · Richelsdorfit
Italian
Richelsdorfite

Classification

Strunz
10th ed.

8.DK

  • 8Phosphates, Arsenates, VanadatesClass
  • 8.DPhosphates, etc. with additional anions, with H2ODivision
  • 8.DKWith large and medium-sized cations, (OH, etc.):RO4 > 1:1 and < 2:1Group
  • 8.DKRichelsdorfiteSpecies
Dana
8th ed.

42.07.15.01

  • 42Hydrated Phosphates, Etc.containing Hydroxyl or HalogenClass
  • 42.07(AB)2(XO4)Zq·xH2OType
  • 42.07.15Richelsdorfite GroupGroup
  • 42.07.15.01RichelsdorfiteSpecies
CIM

22.2.6

  • 22Phosphates, Arsenates or Vanadates with other AnionsClass
  • 22.2Phosphates, arsenates or vanadates with chlorideGroup
  • 22.2.6RichelsdorfiteSpecies

Literature, links & citation

Citations
  1. 1983Süsse, P., Schnorrer-Köhler, G. (1983) Richelsdorfit, Ca2Cu5Sb[Cl(OH)6(AsO4)4]•6H2O, ein neues Mineral [Richelsdorfite, Ca2Cu5Sb[Cl(OH)6(AsO4)4]•6H2O, a new mineral]. Neues Jahrbuch für Mineralogie - Monatshefte, 1983. 145-150
  2. 1984Dunn, Pete J., Grice, Joel D. Fleischer, Michael, Pabst, Adolf (1984) New mineral names. American Mineralogist, 69 (1-2) 210-215
  3. 1987Süsse, Peter, Tillmann, Bruno (1987) The crystal structure of the new mineral richelsdorfite, Ca2Cu5Sb(Cl/(OH)6/(AsO4)4)·6H2O. Zeitschrift für Kristallographie - Crystalline Materials, 179 (1) 323-334 doi:10.1524/zkri.1987.179.1-4.323 DOI: 10.1524/zkri.1987.179.1-4.323
  4. 1994Sarp, H., Dominik, B., Chiappero, P.-J. (1994) Nouveau gisement (Triembach-Le Val, Vosges, France): nouvelles propriétés optiques et diagramme de poudre de la richelsdorfite, Ca2Cu5Sb[Cl(OH)6(AsO4)4]•6H2O. Schweizerische mineralogische und petrographische Mitteilungen 74: 273-277. (in French)
  5. 1995Jambor, John L., Pertsev, Nikolai N., Roberts, Andrew C. (1995) New Mineral Names. American Mineralogist, 80 (7-8). 845-850
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Richelsdorfite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/richelsdorfite-3414},
  note      = {Accessed 2026-05-11}
}