Metallic silvery crystals of the extremely rare thallium mineral rayite from the type locality in India (Dariba Mine, Udaipur District, Udaipur Division, Rajasthan, India). — Photo: David Hospital · CC BY-SA 4.0
Rayite
A monoclinic lead-silver-thallium-antimony sulfosalt identified under the microscope at Rajpura-Dariba, India.
Intro adapted from Wikipedia (CC BY-SA).
Rayite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula (Ag,Tl)₂Pb₈Sb₈S₂₁.
Key properties: specific gravity 6.13; Lead-gray streak; Metallic luster.
IMA symbol Ray, IMA status: approved, named in 1982.
Found in a Precambrian polymetallic massive-sulfide deposit interbedded with kyanite-graphite schists, diopside-bearing calc-silicates, and meta-cherts.
It is found associated with Galena, meneghinite, owyheeite.
The mineral was named to honor Professor Santosh K. Ray (1908–1976), Indian petrologist, President College, Calcutta, India.