Paramelaconite

paramelaconite

Images

Formula: Cu1+2Cu2+2O3
Anhydrous oxide
Crystal System: Tetragonal
Specific gravity: 5.9 to 6.04 measured, 6.106 calculated
Hardness: 4½
Streak: Brown-black
Colour: Black, black with a slight purple tint
Luminescence: Not fluorescent under UV
Solubility: Easily soluble in cold dilute NH4Cl or NH4OH solution, and fragments become coated by a mixture of metallic copper and cupric oxide when placed in extremely dilute mineral acids
Environments

Hydrothermal environments

Paramelaconite is a very rare secondary mineral in hydrothermal copper deposits (HOM). It has an extremely narrow stability region of phase space, with cuprite and tenorite forming readily as competing impurity phases (Mindat).

Localities

At the Tenke Mine, Tenke-Fungurume area, Lualaba, DR Congo, paramelaconite occurs on malachite in cuprite (Mindat photo)
Paramelaconite from the Tenke Mine - Image

At the type locality, the Copper Queen Mine, Queen Hill, Bisbee, Cochise County, Arizona, USA, paramelaconite occurs as a secondary mineral in the following association and sequence:
(matrix: goethite, cuprite) → goethitetenoriteparamelaconite (and minor cuprite) → connellitemalachite.
The paramelaconite alters to tenorite (AM 26.11.657-672).
Paramelaconite from the Copper Queen Mine - Image

At the Algomah Mine, Mass City, Ontonagon County, Michigan, USA, paramelaconite occurs as a very rare secondary mineral in the hydrothermal copper deposits, associated with tenorite, chrysocolla, malachite, plancheite, dioptase and atacamite (HOM).
Paramelaconite from the Algomah Mine - Image

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