Jeromite

General Information:
 Chemical Formula:
As(S,Se)2
 Composition:
(Molecular Weight = 162.50 gm)
Arsenic 46.11 % As
Selenium 24.30 % Se
Sulfur 29.60 % S 
 Empirical Formula:
AsS1.5Se0.5
 Environment:
Sublimate of burning sulfide ores in a mine fire.
 Locality:
United Verde Mine, Jerome, Arizona, USA.
 Name Origin:
Named for the locality
Physical Properties:
 Color:
cherry red, red, or black.
 Streak:
reddish black
More details...