Images
Formula: Ag2Pd3Se4
Selenide of silver and
palladium
Crystal System: Monoclinic
Specific gravity: 8.308 calculated for the ideal formula
Hardness: 5
Streak: Black
Colour: Silvery grey
Luminescence: Not known to fluoresce under UV
Environments
Sedimentary environments
Hydrothermal environments
Localities
At El Chire prospect, General Lamadrid department, La Rioja Province, Argentina, chrisstanleyite has been found
in the telethermal (said of a hydrothermal mineral deposit formed at shallow depth and relatively low temperatures,
with little or no wall-rock alteration, presumably far from the source of hydrothermal solutions - Mindat)
selenide vein deposit, associated with
jaguéite, clausthalite,
naumannite, tiemannite,
klockmannite, berzelianite,
umangite, aguilarite,
amalgam, native gold and
calcite
(HOM).
At Copper Hills, Rudall River District, East Pilbara Shire, Western Australia, chrisstanleyite occurs in
malachite nodules associated with
oosterboschite, naumannite,
berzelianite, umangite,
tiemannite, chalcomenite,
malachite and quartz
(HOM).
At the Eskaborn adit, Tilkerode Mining District, Mansfeld, Mansfeld-Südharz, Saxony-Anhalt, Germany,
chrisstanleyite occurs in a carbonate matrix associated with
clausthalite,
tischendorfite, tiemannite,
stibiopalladinite and gold
(HOM).
At the type locality, Hope's Nose, Torquay, Torbay, Devon, England, UK, one of the high-angled
calcite veins transecting the almost flat-lying shelf of
limestone is the source of the chrisstanleyite. The
mineralisation was found 10 cm below the outcrop of the calcite. It formed a
pocket or lens 10 cm long by 0.07 cm deep by 4 cm wide in which the minerals were distinctly zoned. The sequence from
top to bottom was dendritic or fern-like native gold, with small amounts of
silver, followed by palladium-bearing
gold, then by the selenide
mineralisation.
The selenide assemblage is found as inclusions up to 1 cm in size or as fine
'networks' which have followed cleavage or grain boundaries in calcite. The
complete chrisstanleyite-bearing assemblage, consists of native gold
(argentian and palladian),
fischesserite,
clausthalite, a mineral which is similar to
oosterboschite, verbeekite
and tilkerodeite. Tiny inclusions of
tiemannite, eucairite and
umangite have been observed in the gold
and in the tilkerodeite. Other constituents include a
palladium
arsenide-antimonide, possibly
mertieite, associated with the gold
and cerussite and
bromian chlorargyrite associated with the
selenides.
Chrisstanleyite forms typical monominerallic inclusions in cerussite,
random intergrowths and inclusions in
gold-silver alloys, bordered by
fischesserite or
clausthalite or both, and inclusions in
fischesserite in association with
gold and bromian chlorargyrite.
Occasionally, chrisstanleyite contains inclusions of clausthalite.
Chrisstanleyite occurs as composite grains of anhedral crystals ranging from a few to several hundred microns in
size. It is opaque with a metallic lustre, and a black streak
(MM 62.2.257-264).
Chrisstanleyite from Hope's Nose
Back to Minerals