Exceptionally well formed hatchite crystals (a very rare thallium mineral) from the type and only locality for the mineral worldwide (Switzerland). Associated mineral is realgar and pyrite. Official Code Number: L-14-5693 from the FGL (Forschungsgemeinschaft Lengenbach). — Photo: David Hospital · CC BY-SA 4.0
Hatchite
Hatchite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula AgTlPbAs₂S₅.
It crystallizes in the triclinic crystal system (space group P-1).
Key properties: specific gravity 5.8; Chocolate-brown. R1 –R2: n.d streak.
IMA symbol Hat, grandfathered status — known before the IMA’s founding, named in 1912.
Of hydrothermal origin, in crystalline dolostone.
It is found associated with Wallisite, hutchinsonite, jentschite, sicherite, edenharterite, bernardite, stalderite, lorandite, realgar, orpiment.
The mineral was named to honor Dr. Frederick Henry Hatch (1864–1932), American geologist and mining engineer.