:Locality: Tunaberg, Södermanland, Sweden Size: 0.5 × 0.4 × 0.3 cm Description: Very nice faceted cobaltite crystal from this classic Swedish locality, but more interesting for the pinkish to reddish layer that covers all the specimen. We have analyzed by SEM-EDS and results show that aplowite is present and accompanied by reddish erythrite. — Photo: Joan Rosell , from rosellminerals.com · CC BY-SA 4.0
Aplowite
A very rare hydrated cobalt sulfate — the four-water member of a series that includes bieberite and moorhouseite.
Intro adapted from Wikipedia (CC BY-SA).
Aplowite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Co(SO₄)·4H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/n). It is a member of the Starkeyite structural group.
Key properties: Mohs hardness 3; specific gravity 2.33; White streak; Vitreous luster; optically biaxial.
IMA symbol Apw, IMA status: approved, named in 1963.
Occurs as efflorescences with sulfides (probably cobaltian and nickelian pyrite) on siderite–barite matrix from a hydrothermal Pb–Zn–Cu orebody in association with a large barite deposit.
It is found associated with Moorhouseite, siderite, barite.
The mineral was named to honor Albert Peter Low (1861–1942), Canadian geologist, former Director of the Geological Survey of Canada.