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Formula:
[Pb(H2O)10)][Zn12(OH)20(H2O)(SO4)3]
Sulphate, namuwite group
Crystal System: Triclinic
Specific gravity: 3.27 measured, 3.265 calculated for the empirical formula
Hardness: 2½
Streak: White
Colour: Colourless to pale pink
Luminescence: Haywoodite does not fluoresce under long wave or short wave UV
Solubility: In room-temperature, dilute hydrochloric acid, crystals immediately turn opaque and slowly dissolve
Environments
Metamorphic environments
Hydrothermal environments
Haywoodite is a new mineral, approved in 2021 and to date reported only from the type locality.
Localities
The type locality, the Redmond Mine, Waterville Lake, Haywood County, North Carolina, USA, is a very small and
long-inactive lead - zinc mine with a
highly unusual secondary assemblage of
lead - zinc -
copper sulphates, thiosulphates [compounds containing the anion
(S2O3)2-] and carbonates.
Haywoodite and hanahanite were found underground at the mine. The
ore, composed mainly of galena and
sphalerite with lesser chalcopyrite,
occurs in an epithermal vein system consisting of disconnected sulphide-bearing
quartz lenses near the contact between a
granite gneiss and a
mica schist. Haywoodite and
hanahanite occur in an unusual, localised,
secondary mineral assemblage in vugs in massive
galena -sphalerite -
chalcopyrite - quartz.
Haywoodite occurs with chenite,
cherokeeite, elyite,
lanarkite, redmondite, and
sulfatoredmondite
(CJMP 61.1137-1149).
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