Waterhouseite
An orange-brown bladed manganese hydroxyphosphate.
Intro adapted from Wikipedia (CC BY-SA).
Waterhouseite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Mn₇(PO₄)₂(OH)₈.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: Mohs hardness 4; specific gravity 3.55; Yellowish brown streak; Vitreous to pearly on cleavage surfaces luster; optically biaxial.
IMA symbol Whs, IMA status: approved, named in 2004.
Found in cavities in the carbonate-rich beds of a Precambrian banded iron formation.
It is found associated with Shigaite, gatehouseite, seamanite, rhodochrosite, barite, hausmannite, hematite.
The mineral was named to honor Frederick George Waterhouse (1815-1898), first Director of the South Australian Museum (Adelaide).