Holotype specimen of richardsollyite (dark grey) with hutchinsonite (dark red) and realgar. Field of view: 3.5 mm. Mineralogical Collection of the Musée cantonal de géologie (MGL no. 080126), photo: Stefan Ansermet. From Lengenbach quarry. — Photo: Stefan Ansermet · CC BY 4.0
Richardsollyite
Richardsollyite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula TlPbAsS₃.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: Mohs hardness 3–3.5; specific gravity 3.692; Black streak; Metallic luster.
IMA symbol Rsy, IMA status: approved, named in 2016.
Found in vugs in lenses and ribbons of recrystallized metadolostone.
It is found associated with Hutchinsonite, barite, Tl-bearing dufrénoysite, realgar, pyrite, dolomite.
The mineral was named to honor Richard Harrison Solly (1851-1925) for his contributions to the mineralogy of Lengenbach during the period of investigations, at the beginning of the 20th Century.