Krautite , Villyaellenite Field of view: 15 mm Locality: Săcărâmb, Certeju de Sus, Hunedoara County, Romania Description: Pink krautite with tan villyaellenite. Daughter photo showing the entire specimen. Purchased from Jaroslav Hyrsl in Tucson in February 2016. Modified by CombineZP, stacking 4 images. — Photo: Michael J Pabst · CC BY 3.0
Villyaellenite
Villyaellenite is an IMA-recognized mineral species in the arsenate class, with the chemical formula (Mn,Ca)Mn₂Ca₂(AsO₃OH)₂(AsO₄)₂·4H₂O.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Hureaulite structural group.
Key properties: Mohs hardness 4; specific gravity 3.2–3.69; White streak; Vitreous luster; optically biaxial.
IMA symbol Vy, IMA status: approved, named in 1983.
A rare post-mine low-temperature reaction product of carbonate gangue with arsenical solutions derived from arsenic (Sainte-Marie-aux-Mines, France).
It is found associated with Fluckite, picropharmacolite, pharmacolite, arsenic (Sainte-Marie-aux-Mines, France); ogdensburgite, arseniosiderite, chalcophanite, adamite.
The mineral was named to honor Dr. Villy Aellen, Director, Natural History Museum, Geneva, Switzerland.