Outstanding colorless single crystal aggregate of the extremely rare NH4-Fe-sulphate minerals lonecreekite, sabieite and clairite from the type locality for all of them in Lone Creek Falls, Sabie, Southafrica. Ex Vandenbroucke Museum collection from Waregem, Belgium. Analyzed specimen by the former owner of the specimen. — Photo: David Hospital · CC BY 4.0
Clairite
Clairite is an IMA-recognized mineral species in the sulfate class, with the chemical formula (NH₄)₂Fe³⁺₃(SO₄)₄(OH)₃·3H₂O.
It crystallizes in the triclinic crystal system.
Key properties: specific gravity 2.31; optically biaxial.
IMA symbol Clai, IMA status: approved, named in 1982.
A rare secondary mineral produced through alteration of pyrite to ferric sulfate, and reaction, at pH ∼2, with ammonia produced as the result of decay of organic matter (Hyrax excreta).
It is found associated with Lonecreekite, sabieite, tschermigite.
The mineral was named to honor Claire Zingg Martini (1936–), wife of the author of the type description, who assisted her husband in cave exploration and mineral collecting.