White crystal aggregates of the rare aluminium phosphate sulphate from a locality very close to the type locality in Southafrica: Pella, Orange River, Northern Cape Province, South Africa. — Photo: David Hospital · CC BY-SA 4.0
Hotsonite
A hydrated aluminium phosphate-sulfate named for the Hotson farm in South Africa's arid Bushmanland.
Intro adapted from Wikipedia (CC BY-SA).
Hotsonite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Al₅(SO₄)(PO₄)(OH)₁₀·8H₂O.
It crystallizes in the triclinic crystal system.
Key properties: Mohs hardness 2.5; specific gravity 2.06–2.07; Silky to dull, earthy luster; optically biaxial.
IMA symbol Hot, IMA status: approved, named in 1983.
A weathering product derived from natroalunite and zaherite in an arid climate (Koenabib, South Africa).
It is found associated with Zaherite, natroalunite, sillimanite (Koenabib, South Africa).
The name refers to Hotson 42, the farm in South Africa on which the first specimens were collected.