Redgillite - Germany, North-Rhine Westphalia, Arnsberg, Burbach, Schöne Aussicht Mine - 3 mm. Photos from tomeikminerals.com can be used under a Creative Commons Licenese 4.0 CC-BY, as explained in: https://www.tomeikminerals.com/about-me . — Photo: Henk Smeets - Tomeik Minerals · CC BY 4.0
Redgillite
Redgillite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Cu₆(SO₄)(OH)₁₀·H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: Mohs hardness 2; specific gravity 3.45; White streak; Vitreous luster; optically biaxial.
IMA symbol Rgl, IMA status: approved, named in 2004.
A secondary weathering mineral in oxidized copper sulfide veins and post-mining environments.
It is found associated with Langite, malachite, cuprite, connellite, brochantite.
The name refers to the Red Gill Mine, England, the locality from which the mineral is best known.