Very small black inclusions of the rare Hg mineral tvalchrelidzeite from Getchell mine (Humboldt County, Nevada, United States of America). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Tvalchrelidzeite
Tvalchrelidzeite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula Hg₃SbAsS₃.
It crystallizes in the monoclinic crystal system (space group P2_1/n).
Key properties: Mohs hardness 3; specific gravity 7.38; Nearly black, with a dark reddish tint streak; Adamantine luster.
IMA symbol Tva, IMA status: approved, named in 1974.
Found in gold-bearing hydrothermal As–Sb–Hg deposits.
It is found associated with Cinnabar, metacinnabar, realgar, mercurian tennantite, mercury, cubanite, pyrrhotite, chalcopyrite, marcasite, fluorite, quartz.
In honor of Academician Aleksander Antonovich Tvalchrelidze (1881–1957), founder of the Georgian Mineralogical-Petrographic School, Tbilisi University, Tbilisi, Georgia.