Macquartite

General Information:
 Chemical Formula:
Pb3Cu(CrO4)(SiO3)(OH)4·2(H2O)
 Composition:
(Molecular Weight = 981.28 gm)
Chromium 5.30 % Cr
Copper 6.48 % Cu
Silicon 2.86 % Si
Hydrogen 0.82 % H 
Lead 63.35 % Pb
Oxygen 21.20 % O 
 Empirical Formula:
Pb3Cu(CrO4)(SiO3)(OH)4·2(H2O)
 Environment:
Encrusting dioptase.
 IMA Status:
Approved IMA 1979
 Locality:
Mammoth mine, Tiger, Pinal County, Arizona, USA.
 Name Origin:
Named for Louis Charles Henri Macquart (1745-1803), French chemist who brought to France from Russia the samples of crocoite in which the element chromium was discovered.
Physical Properties:
 Cleavage:
[100] Good
 Color:
orange.
 Density:
5.49
 Habits:
Euhedral Crystals - Occurs as well-formed crystals showing good external form., ,
 Hardness:
3.5 - Copper Penny
 Luster:
Adamantine
 Streak:
light orange
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