General Information:
Chemical Formula:
Hg3S2(Br,Cl,I)2
Composition:
(Molecular Weight = 817.84 gm)
Mercury 73.58 % Hg
Sulfur 7.84 % S
Iodine 6.21 % I
Bromine 9.77 % Br
Chlorine 2.60 % Cl
Empirical Formula:
Hg3S2BrCl0.6I0.4
Environment:
In the oxidation zone in fractures of a mercury deposit.
IMA Status:
Approved IMA
Locality:
Arzak and Kadyrel mercury deposits, Tuva, Siberia, Russia.
Name Origin:
Named for Oleg Konstantinovich Grechishchev, Russian engineering geologist, long-time student of mercury ores from Tuva, Siberia.
Physical Properties:
Cleavage:
[???] Good
Color:
brownish black, orange, or reddish orange.
Density:
7.16
Diaphaniety:
Transparent
Habits:
Microscopic Crystals - Crystals visible only with microscopes., Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).,
Hardness:
2.5 - Finger Nail
Luster:
Vitreous - Adamantine
Streak:
deep yellow
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