Polished section of the intermediate member of the series hollingworthite and irarsite in a completley analyzed specimen. From: Goodnews Bay, Bethel Borough, Alaska, United States of America. The hollingworthite is clearly marked on the analyzed cylinder. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Hollingworthite
Hollingworthite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula RhAsS.
It crystallizes in the cubic crystal system (space group P2_13). It is a member of the Ullmannite structural group.
Key properties: Mohs hardness 6; specific gravity 7.86.
IMA symbol Hlw, IMA status: approved, named in 1964.
Found in platinum deposits in dunite pipes, layered ultramafic intrusives, and chromatites; in Cu–Ni sulfide ores.
It is found associated with Sperrylite, geversite, erlichmanite, irarsite, Pt–Fe alloys (South Africa); chalcopyrite, cobaltite, gersdorffite, pyrrhotite (Canada); Au–Ag alloy, braggite.
The mineral was named to honor Professor Sidney Ewart Hollingworth (1899–1966), eminent British geologist, University College, London, England.