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
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