Chalcophanite

chalcophanite

cryptomelane

hetaerolite

birnessite

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Formula: ZnMn4+3O7.3H2O
Multiple oxide, chalcophanite group
Crystal System: Trigonal
Specific gravity: 3.907 to 4.1 measured, 3.85 calculated
Hardness: 2½
Streak: Dark brown, red-brown
Colour: Iron-black, bluish black, dark red (in thin plates)
Solubility: Soluble in hydrochloric acid
Environments

Hydrothermal environments

Chalcophanite is a common component of the weathered zones above zinc and manganese bearing base metal deposits. Associated minerals include cryptomelane, manganite, hetaerolite, birnessite, todorokite, woodruffite, kaolinite and quartz (HOM).

Localities

At the Kintore opencut, Broken Hill South Mine, Broken Hill district, Yancowinna county, New South Wales, Australia, chalcophanite occurs as crystals to 1 mm on coronadite and goethite. It has been found with smithsonite and chlorargyrite and with smithsonite and hemimorphite (AJM 3.1.31).

At the Red Lead Mine, Dundas mineral field, Zeehan district, West Coast municipality, Tasmania, Australia, chalcophanite is a common associate of crocoite (AJM 12.2.76).

At the Wolftone Mine, Carbonate Hill, Leadville, Lake county, Colorado, USA, chalcophanite occurs with limonite, smithsonite and hemimorphite (Dana).

At the type locality, the Passaic pit, Sterling Hill, Ogdensburg, Franklin Mining District, Sussex County, New Jersey, USA, chalcophanite occurs in the oxidation zone of a franklinite and zincite deposit, associated with zincite, willemite, quartz and franklinite (Mindat).

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