Hutchinsonite Locality: Quiruvilca Mine (La Libertad Mine; ASARCO Mine), Quiruvilca District , Santiago de Chuco Province , La Libertad Department , Peru ( Locality at mindat.org ) Size: 4.5 x 4.4 x 2.2 cm. This is one of the richest examples of the species out there. It is by far the richest piece I have seen for this rare thallium-rich sulfosalt. Not the biggest, but the most richly crystallized. It is composed of extremely robust, diverging sprays of acicular hutchinsonite crystals, many doubly terminated. The crystals, to .75 cm across, are lustrous, dark gray, and nearly cover the host matrix. This is an amazing specimen of the rare lead, thallium, sulpharsenide. From the collection of my mentor, Carlton Davis. Acquired in the early 1980s from dealer Gary Hansen. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Hutchinsonite
A rare thallium-arsenic-lead sulfosalt found in 1903 at Binnental, Switzerland, named for Cambridge mineralogist Arthur Hutchinson.
Intro adapted from Wikipedia (CC BY-SA).
Hutchinsonite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula TlPbAs₅S₉.
It crystallizes in the orthorhombic crystal system (space group Pbca).
Key properties: Mohs hardness 1.5–2; specific gravity 4.6–4.7; Adamantine to submetallic luster; optically biaxial.
IMA symbol Hut, grandfathered status — known before the IMA’s founding, named in 1905.
Hydrothermal in origin.
It is found associated with Orpiment, realgar, getchellite, pyrite, sphalerite, hatchite, jentschite, sicherite, edenharterite, bernardite, stalderite, ernigglite, chabournite.
The mineral was named to honor Arthur Hutchinson (1866–1937), Professor of Mineralogy, Cambridge University, Cambridge, England.