Wattevilleite

Na2Ca(SO4)2 · 4H2O (?)
IMA status
  • Approved
  • Grandfathered
  • Questionable
IMA symbol
Wtv
Also known as
  • Wattevilleiet
  • Wattevillite

Where it forms, where it's found

Geological setting

Pyritic lignite deposit.

Type locality
Einigkeit Mine
  1. Bauersberg
  2. Bischofsheim in der Rhön
  3. Rhön-Grabfeld District
  4. Lower Franconia
  5. Bavaria
  6. Germany

50.4203°, 10.0364°

10recorded occurrences
Source · OpenStreetMap

Physical

Transparency
Translucent
Colour
White
Density
1.81 g/cm³

Optical

Optical type
Biaxial (-) · 2V measured = 48° · 2V calc = 46°
Refractive index
1.435 – 1.459
Surface relief
Low
Principal indices
nα 1.435 · nβ 1.455 · nγ 1.459
Dispersion
dispersion not observed
Michel-Lévy diagramhighlighted lineδ = 0.0240
Attainable Michel-Lévy rangeΔ ∈ [0, t·δmax]240 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°
Retardation240 nm
Order1st order
XPL colour

Crystallography

Crystal system
Orthorhombic
Morphology

Minute acicular, in part twinned.

Twinning

noted

Type-locality form

Tiny acicular white crystals

Comment

Point Group: n.d.; Space Group: n.d. Z = n.d.

Synonyms

  • Wattevilleiet
  • Wattevillite

In other languages

German
Wattevilleit
Italian
wattevilleite · Wattevillite
Chinese
灰芒硝

Classification

Strunz
10th ed.

7.CC.85

  • 7SulfatesClass
  • 7.CSulfates (selenates, etc.) without additional anions, with H2ODivision
  • 7.CCWith medium-sized and large cationsGroup
  • 7.CC.85WattevilleiteSpecies
Dana
8th ed.

29.03.04.01

  • 29Hydrated Acid and Normal SulfatesClass
  • 29.03A2B(XO4)2·xH2OType
  • 29.03.04— unnamed intermediate level —Group
  • 29.03.04.01WattevilleiteSpecies

Literature, links & citation

Citations
  1. 1879Singer S (1879) Wattevillit. in Beiträge zur Kenntniss der am Bauersberge bei Bischofsheim vor der Rhön vorkommenden Sulfate, Becker's Universitäts-Buchdruckerei (Würzburg) 18-20
  2. 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.
  3. 1985Sabelli C, Trosti-Ferroni R. (1985) A structural classification of sulfate minerals. Periodico di Mineralogia: 54: 1-46.
  4. 2005(2005) Wattevilleite. Handbook of Mineralogy. Mineralogical Society of America
  5. 2007Leverett, P., Williams, P.A. (2007) Unusual post-mining sulfates from the Peelwood and Lloyd mines, New South Wales, and a comment on wattevilleite. Australian Journal of Mineralogy, 13(1), 41-46.
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Wattevilleite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/wattevilleite-4249},
  note      = {Accessed 2026-05-11}
}