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Formula: Cu2Ca6[Si6O17(OH)](CO3)(OH)3(H2O)2
Inosilicate (chain silicate) with single and multiple chains
Crystal system: Orthorhombic
Specific gravity: 2.74 measured, 2.738 calculated for the empirical formula 2.856 calculated for the ideal formula
Hardness: 2½
Streak: Pale blue
Colour: Pale blue, greenish blue
Environments
Localities
At the Christmas Mine, Christmas, Banner Mining District, Gila County, Arizona, USA, whelanite is associated
with gilalite, ruizite,
stringhamite, tobermorite,
andradite, bornite,
calcite, chalcopyrite,
quartz and wollastonite
(HOM).
Whelanite from the Christmas Mine -
Image
At the Sunrise copper prospect, Nelson Range, Lee Mining District, Inyo County, California, USA, whelanite
is associated with apophyllite,
lepidocrocite,
stringhamite, thaumasite,
bornite, calcite,
diopside, grossular and
tenorite
(HOM).
At the Crestmore quarries, Crestmore, Jurupa Valley, Riverside County, California, USA, some of the massive
garnet-wollastonite zone is
composed of very fine, sugary grossular, and fracture surfaces
in this mass are often characterised by the presence of foshagite in
"slip-fibre" form, like asbestos, or painted over with a thin coating of brilliant blue whelanite. The
whelanite may occur alone on a surface, or in combination with
foshagite, or less often as pellet-like aggregates of thin blades
occurring in calcite, just like the metallic sulphides
(AM, 46.245-257, as mineral Y).
Asssociated minerals include wayneburnhamite,
vesuvianite, wollastonite,
grossular, cerussite and
nasonite
(HOM), as well as ganomalite,
stringhamite, thaumasite
and tobermorite, on rock containing
calcite and galena
(AM 97.11.2007-2015).
The type locality is the Bawana Mine, Rocky Mining District, Rocky Range, Beaver County, Utah, USA. At all of the
localities whelanite is found as a late-stage phase in copper-rich,
calc-silicate skarn assembages. At the Bawana mine, it occurs with
kinoite, stringhamite and
thaumasite on rock containing
diopside, garnet
(grossular–andradite),
goethite, magnetite and
tenorite. Chrysocolla
(including a blue copper-bearing silica gel) is abundant in the deposit and
may occur on or near specimens containing whelanite and/or
stringhamite. The whelanite was found as irregular clusters and
radial aggregates of platy to lath-like crystals up to 1 mm in length.
After mining ceased at the Bawana mine, whelanite and associated
stringhamite were found only within a small area of
skarn rubble near the midpoint of the bottom of the open pit. Several
decades of mineral collecting have depleted the occurrence, such that at the present time it is difficult or
impossible to find specimens of these minerals
(AM 97.11.2007-2015).
Whelanite from the Bawana Mine - Image
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