General Information:
Chemical Formula:
AuPb(Sb,Bi)Te2-3S6
Composition:
(Molecular Weight = 1,059.12 gm)
Bismuth 4.93 % Bi
Antimony 8.62 % Sb
Tellurium 30.12 % Te
Lead 19.56 % Pb
Gold 18.60 % Au
Sulfur 18.17 % S
Empirical Formula:
AuPbSb0.75Bi0.25Te2.5S6
Name Origin:
Named after the deposit Nagyag (now Sacaramb), Romania.
Physical Properties:
Cleavage:
[010] Perfect
Color:
lead gray or black.
Density:
7.5
Diaphaniety:
Opaque
Habits:
Granular - Generally occurs as anhedral to subhedral crystals in matrix., Lamellar - Thin laminae producing a lamellar structure., Platy - Sheet forms (e.g. micas).
Hardness:
1.5-2 - Talc-Gypsum
Luminescence:
None.
Luster:
Metallic
Streak:
gray black
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