Rayite

General Information:
 Chemical Formula:
(Ag,Tl)2Pb8Sb8S21
 Composition:
(Molecular Weight = 3,568.98 gm)
Thallium 2.86 % Tl
Silver 4.53 % Ag
Antimony 27.29 % Sb
Lead 46.44 % Pb
Sulfur 18.87 % S 
 Empirical Formula:
Ag1.5Tl0.5Pb8Sb8S21
 IMA Status:
Approved IMA
Physical Properties:
 Cleavage:
None
 Color:
lead gray or gray.
 Density:
6.13
 Diaphaniety:
Opaque
 Hardness:
2.5 - Finger Nail
 Luster:
Metallic
 Streak:
lead gray
More details...