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Formula: PbZn2(AsO4)2.2H2O
Hydrated arsenate,
tsumcorite group
Crystal System: Monoclinic
Specific gravity: 5.2
Hardness: 4½
Streak: Yellow
Colour: Yellow-brown, red-brown, orange
Solubility:
Common impurities: Fe3+
Environments:
Tsumcorite is a rare secondary mineral in the oxidised
zone of some arsenic-bearing
hydrothermal lead-zinc deposits.
It forms a series with helmutwinklerite and
thometzekite
(Webmin).
Localities
At the Puttapa mine, South Australia, tsumcorite is associated with
adamite,
mimetite, smithsonite,
goethite and quartz
(HOM).
Tsumcorite has been found in a sample from Thrasos, Greece, in the British museum collection
(AM 57.1558).
At the type locality, the Tsumeb Mine, Namibia, tsumcorite is found in the oxidised zone associated with
willemite, smithsonite,
mimetite, scorodite,
anglesite,
arseniosiderite,
beaverite,
beudantite, carminite,
ludlockite, o’danielite,
zincroselite,
stranskiite and leiteite
(HOM).
Pseudomorphs of tsumcorite after
mimetite have been found here
(KL p198).
Tsumcorite from the Tsumeb Mine - Image
At the Tintic Mining District, Utah, USA, Fine yellow crystals and crystal groups of tsumcorite have been
found at the Centennial Eureka and Mammoth mines. The crystals reach about 1 mm in size and are elongated,
spear-shaped, or flattened plates, usually occurring in clusters. They most commonly occur in vugs in
quartz where most of the
primary minerals have altered. Tsumcorite is usually
associated with mimetite and other
arsenate minerals
(MinRec 55.2.226).
Tsumcorite from Tintic - Image
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