Alperiste , Slavíkite (File of view: 12 mm) Locality: Prenterwinkelgraben (Bärndorfer Graben), Bärndorf, Rottenmann, Liesing - Palten valley, Styria, Austria Original description: Anhedral grains and aggregates of alpersite (white, with very slight greenish tint; SXRD- and EDS-analysed) on pale yellow-brown crusts of slavikite (PXRD- and EDS-analysed). This specimen is described in Kolitsch, U. (2014): 1992) Alpersit und Slavikit vom Prenterwinkelgraben bei Barndorf, Paltental, Steiermark. P. 137 in Niedermayr, G. et al. (2014): Neue Mineralfunde aus Österreich LXIII. Carinthia II, 204./124., 65-146. — Photo: Harald Schillhammer · CC BY-SA 3.0 de
Alpersite
A magnesium-copper sulfate heptahydrate named for USGS geochemist Charles Alpers.
Intro adapted from Wikipedia (CC BY-SA).
Alpersite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Mg(SO₄)·7H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/c). It is a member of the Melanterite structural group.
Key properties: Mohs hardness 2.5; specific gravity 1.82; White streak; Vitreous luster; optically biaxial.
IMA symbol Aps, IMA status: approved, named in 2003.
An efflorescent secondary mineral, likely widespread and unnoticed in mine wastes that contain copper-bearing sulfides.
It is found associated with Pickeringite, alunogen, epsomite, gypsum.
The mineral was named to honor Charles N. Alpers, geochemist with the United States Geological Survey.