Very pale yellow crystals of the rare mineral thorikosite from the type locality in Lavrion: Passa Limani Cove, Lavrion, Attiki Prefecture, Greece. Thorikosite has been found in only 3-4 localities worldwide. — Photo: David Hospital · CC BY-SA 4.0
Thorikosite
Thorikosite is an IMA-recognized mineral species in the halide class, with the chemical formula Pb₃O₃Sb³⁺(OH)Cl₂.
It crystallizes in the tetragonal crystal system (space group I4/mmm).
Key properties: specific gravity 7.24; Vitreous luster.
IMA symbol Thk, IMA status: approved, named in 1984.
A rare secondary mineral formed through alteration of lead-bearing slag by sea water.
It is found associated with Paralaurionite, laurionite, hydrocerussite, sphalerite, calcite, aragonite.
The name refers to Thorikos, an ancient town in Greece, where ores obtained from the nearby Laurium mines were smelted.