General Information:
Chemical Formula:
Tl2(As,Sb)8S13
Environment:
Found in vuggy masses of barite, in barite and calcite veins, and in the silty, carbonaceous limestone host.
IMA Status:
Approved IMA
Locality:
Mercur gold deposit, Tooele County, Utah, USA.
Name Origin:
Named in honor of the late James C. Gilluly, United States Geological Survey.
Physical Properties:
Cleavage:
[???] Perfect
Color:
red, maroon, dark red, or blue.
Density:
4.022
Diaphaniety:
Translucent
Habits:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., ,
Hardness:
2-2.5 - Gypsum-Finger Nail
Luster:
Sub Metallic
Streak:
red
More details...