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Formula: Cu3(Mo6+O4)2(OH)2
Anhydrous molybdate
Crystal System: Monoclinic
Specific gravity: 4.2 measured, 4.29 calculated
Hardness: 4½
Streak: Pale green
Colour: Green, yellowish green, pale green to yellow-green in transmitted light
Solubility: Readily soluble in HCl and HNO3.
Environments
Lindgrenite is an uncommon secondary mineral in the oxidised zone of
molybdenum-bearing copper deposits. Associated
minerals include antlerite, molybdenite,
powellite, brochantite,
chrysocolla, limonite,
iron oxides and
quartz
(HOM, Mindat).
Localities
At Tierra Amarilla, Copiapó Province, Atacama, Chile, lindgrenite occurs with szenicsite
(Dana).
At the type locality, the Chuquicamata mine, Chuquicamata District, Calama, El Loa Province, Antofagasta, Chile, lindgrenite occurs
in veinlets in limonitic quartz
(AM 20.484-491), associated with quartz, antlerite,
limonite and hematite
(Dana, Mindat).
At the Childs-Adwinkle mine, Copper Creek, Bunker Hill District, Pinal county, Arizona, USA, lindgrenite occurs as patches of minute
crystals, usually occurring in divergent clusters with brochantite
(R&M 96.2.155).
At the Tussel Occurrence, Seven Devils District, Adams county, Idaho, USA, lindgrenite occurs on
tactite collected from the mine dump. The specimen came from a contact between
diorite and marble. The matrix of the
lindgrenite is hard granular tactite composed largely of
quartz with subordinate amounts of hastingsite,
epidote and garnet.
Prior to oxidation the rock contained abundant bornite,
molybdenite, a few grains of
molybdenum-bearing scheelite, and probably
carbonate minerals. Oxidation has converted the bornite almost completely to
limonite, and its copper content has been dispersed
in chrysocolla, brochantite, lindgrenite,
and other secondary copper minerals. Some
of the molybdenite is still present as bright silvery plates. Elsewhere
molybdenite has been altered to pseudomorphs of
powellite. A second variety of pale green powellite
partly fills a cavity lined with quartz crystals and is thought to be of
supergene origin. The molybdenum-bearing
scheelite is the least affected of the ore minerals, but on most of the grains an outer shell
has been altered to cuprotungstite.
The lindgrenite occurs as veinlets, crusts, and possibly minor replacements of
pseudomorphous powellite. Some cavities formerly
occupied by molybdenite are now lined with drusy crusts of lindgrenite
(AM 38.903-911).
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