Scotlandite
A rare lead sulfite — one of the few sulfite minerals — from the lead veins of Leadhills, Scotland.
Intro adapted from Wikipedia (CC BY-SA).
Scotlandite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Pb(S⁴⁺O₃).
It crystallizes in the monoclinic crystal system (space group P2_1/m).
Key properties: Mohs hardness 2; specific gravity 6.37; Adamantine to resinous, pearly on cleavages luster; optically biaxial.
IMA symbol Sct, IMA status: approved, named in 1982.
A very rare secondary mineral, formed in the oxidized zone of hydrothermal lead deposits.
It is found associated with Pyromorphite, anglesite, lanarkite, leadhillite, susannite, barite (Leadhills, Scotland); leadhillite, susannite, macphersonite, cerussite, pyromorphite.
The name refers to Scotland, within which the first specimen was found.