Wermlandite
Wermlandite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Mg₇Al₂(OH)₁₈[Ca(H₂O)₆](SO₄)₂·6H₂O.
It crystallizes in the hexagonal crystal system (space group P-3c1). It is a member of the Woodwardite, Hydrotalcite structural group.
Key properties: Mohs hardness 1.5; specific gravity 1.932; optically uniaxial.
IMA symbol Wld, IMA status: approved, named in 1970.
Very rare in a metamorphosed Fe–Mn orebody in a low-temperature fissure-filling assemblage among large calcite crystals.
It is found associated with Calcite, magnetite.
The name refers to Wermland, an earlier spelling of the Swedish province Värmland, in which the Långban deposit is located.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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