Images
Formula: Cu2(NO3)(OH)3
Nitrate, orthorhombic paramorph of monoclinic
rouaite
Crystal System: Orthorhombic
Specific gravity: 3.4 to 3.43 measured, 3.389 calculated
Hardness: 2
Streak: Light green
Colour: Emerald Green
Solubility: Insoluble in water, soluble in dilute acids
Environments
Gerhardtite is a rare secondary mineral in oxidised
portions of copper deposits. Associated minerals include
cuprite, malachite,
atacamite, miersite,
brochantite, pseudomalachite,
buttgenbachite, likasite,
connellite and claringbullite
(HOM).
Localities
The Great Australia mine, Cloncurry, Cloncurry Shire, Queensland, Australia, hosts an unusual enrichment in
gerhardtite. It is probable that oxidised ammonia from nearby termite mounds provides the nitrate required for
gerhardtite mineralisation
(CM 44.1447-1455).
Gerhardtite from the Great Australia Mine -
Image
At the type locality, the United Verde mine, Jerome, Verde Mining District, Black Hills, Yavapai County, Arizona, USA,
gerhardtite occurs in cavities in cuprite
(Dana).
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