Pearly Kuzelite (Picture size: 1.7 mm) Locality: Bellerberg, Eifel, Rhineland-Palatinate, Germany — Photo: Thomas Witzke · CC BY-SA 3.0 de
Kuzelite
Kuzelite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Ca₄Al₂(OH)₁₂(SO₄)·6H₂O.
It crystallizes in the hexagonal crystal system (space group R-3). It is a member of the Hydrotalcite structural group.
Key properties: Mohs hardness 1–2; specific gravity 1.99; White streak; Vitreous luster; optically uniaxial.
IMA symbol Kuz, IMA status: approved, named in 1996.
A rare mineral found in carbonaceous xenoliths in basalt, formed above 100 ° C by decomposition of ettringite.
It is found associated with Ettringite, afwillite, natrolite, calcite, torbermorite, gyrolite, portlandite, apophyllite (Zeilberg quarry, Germany); hydrocalumite, ettringite, tobermorite.
The mineral was named to honor Professor Hans Jürgen Kuzel (1932–1997), German mineralogist, Mineralogical Institute, Erlangen, Germany, who first synthesized the compound.