Light purplish Petterdite (Picture size: 2.5 mm) Locality: Callenberg Nord II open cast, Callenberg near Glauchau, Saxony, Germany — Photo: Thomas Witzke · CC BY-SA 3.0 de
Petterdite
Petterdite is an IMA-recognized mineral species in the carbonate class, with the chemical formula PbCr₂(CO₃)₂(OH)₄·H₂O.
It crystallizes in the orthorhombic crystal system (space group Pbnm). It is a member of the Dundasite structural group.
Key properties: Mohs hardness 2; specific gravity 3.947; Pale violet streak; Pearly to earthy luster; optically biaxial.
IMA symbol Pte, IMA status: approved, named in 1999.
A rare secondary species probably produced through alteration of galena by Cr-bearing meteoric waters (Red Lead mine, Australia); in the oxidation zone of a hydrothermal vein cutting serpentinite (Callenberg mine, Germany).
It is found associated with Anglesite, crocoite, “limonite” (Red Lead mine, Australia); crocoite, cerussite, bindheimite, pyromorphite, galena (Callenberg mine, Germany).
The mineral was named to honor William Frederick Petterd (1849–1910), mineral collector who published several catalogs of Tasmanian mineral occurrences.