White crystal aggregates of the rare Ca arsenate mineral weilite associated to pink erythrite from Germany (Richelsdorf District, Wildeck, Hesse, Germany). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Weilite
A translucent white waxy calcium hydrogen arsenate described in 1963 from Alsace and Saxony.
Intro adapted from Wikipedia (CC BY-SA).
Weilite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Ca(AsO₃OH).
It crystallizes in the triclinic crystal system (space group P-1).
Key properties: specific gravity 3.48; Porcelaneous, may be greasy to slightly pearly luster; refractive index 1.666; optically biaxial.
IMA symbol Wei, IMA status: approved, named in 1963.
A rare secondary mineral found in the oxidized zone of arsenic-bearing hydrothermal mineral deposits.
It is found associated with Pharmacolite, haidingerite, picropharmacolite.
The mineral was named to honor Professor René Weil (1901–), French mineralogist, University of Strasbourg, Strasbourg, France.