Lindgrenite

Lindgrenite is an uncommon copper molybdate mineral with formula: Cu3(MoO4)2(OH)2. It occurs as tabular to platey monoclinic green to yellow green crystals.

Lindgrenite
Lindgrenite specimen from the San Samuel Mine of the Cachiyuyo de Llampos district, Copiapó Province, Atacama Region, Chile (field of view 4 mm)
General
CategoryMolybdate mineral
Formula
(repeating unit)
Cu3(MoO4)2(OH)2
IMA symbolLgr[1]
Strunz classification7.GB.05
Dana classification48.3.1.1
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/n
Unit cella = 5.394, b = 14.023
c = 5.608 [Å]; β = 98.5°; Z = 2
Identification
ColorGreen to yellowish green
Crystal habitTabular to platey crystals, may be acicular, massive or crust forming
CleavagePerfect on {010} and {101}, poor on {100}
FractureMicaceous
TenacityBrittle
Mohs scale hardness4.5
LusterGreasey
StreakPale green
DiaphaneityTransparent
Specific gravity4.2
Optical propertiesBiaxial (-)
Refractive indexnα = 1.930 nβ = 2.002 nγ = 2.020
Birefringenceδ = 0.090
2V angle71° (measured)
References[2][3][4]

Discovery and occurrence

It was first described in 1935 for an occurrence in the Chuquicamata Mine, Antofagasta, Chile, and named for Swedish–American economic geologist Waldemar Lindgren (1860–1939) of the Massachusetts Institute of Technology.[2][3]

Lindgrenite occurs in the oxidized portions of copper–molybdenum bearing sulfide ore deposits. Associated minerals include antlerite, molybdenite, powellite, brochantite, chrysocolla, iron oxides and quartz.[2]

Lindgrenite in a quartz vug from the type locality of Chuquicamata (size: 1.7 x 1.7 x 1.4 cm)
Lindgrenite, Inspiration mine, Arizona. Size 2 cm.

References

Further reading

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