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Formula: Cu8(Si4O11)2(OH)4.H2O
Inosilicate (chain silicate)
Crystal System: Orthorhombic
Specific gravity: 3.65 to 3.80 measured, 3.85 calculated
Hardness: 5
Streak: Light blue
Colour: Pale to dark blue
Environments:
Plancheite is a rare secondary mineral in the oxidised portion of
copper deposits, associated with
chrysocolla,
dioptase,
malachite, conichalcite and
tenorite
(HOM).
Localities
At the Renéville Mine, Renéville, Kindanba District, Pool Department, Republic of the Congo, fine specimens of
plancheite have been found; associated minerals include dioptase,
chrysocolla and chalcocite
(MinRec 55.4.436).
Plancheite from the Renéville Mine -
Image
At the type locality, the Sanda Hills occurrences, Mindouli, Mindouli District, Pool Department, Republic of the
Congo, plancheite occurs as dark blue concretions with a rounded surface and very tight fibrous structure,
light blue spherules composed of randomly oriented needles and asbestiform veinlets in
sandstone, to 4 cm in length.
Associated minerals include silver,
dioptase, cuprite,
chalcocite and calcite
(Mindat).
Planchite from the Sanda Hills occurrences -
Image
At Table mountain mine, Pinal county, Arizona, USA, plancheite occurs with compact
conichalcite
(Dana).
Plancheite from the Table Mountain Mine -
Image
At the Mufulira Mine, Mufulira, Mufulira District, Copperbelt Province, Zambia, small amounts of plancheite
were recovered from the 640-meter level at Mufulira West in the 1970s. The specimens are cerulean blue, fibrous,
radiating globular masses up to 1 cm across, associated with malachite on
oxidised quartzite
(MinRec 55.4.474).
Plancheite from Mufulira - Image
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