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Formula: CdS
Valence: Cd2+S2-
Simple sulphide of cadmium,
wurtzite group,
paramorph of
hawleyite
Crystal System: Hexagonal
Specific gravity: 4.8 to 4.9 measured 4.824 calculated
Hardness: 3 to 3½
Streak: Orange-yellow to brick red
Colour: Yellow to red.
Common impurities: Zn
Environments
Igneous environments
Hydrothermal environments rarely
Greenockite occurs as earthy coatings, especially on sphalerite, rarely as
crystals in cavities in mafic igneous rocks, and in high-temperature hydrothermal
vein deposits. Associated minerals include sphalerite,
smithsonite, prehnite and
zeolites at low temperature, and
cassiterite, tetrahedrite,
herzenbergite, chalcopyrite
and other sulphides at high temperature
(HOM, Mindat).
Localities
At the South Comet Mine, Dundas, Tasmania, Australia, some sphalerite
crystals have a coating of greenockite
(AJM 12.2.72).
Greenockite from the Great South Comet Mine -
IMage
At Llallagua, Rafael Bustillo, Potosí, Bolivia, greenockite is widespread in small quantities as tiny crystals.
It is bright brick-red, rather than the yellow colour typical of other world localities. Specimens occur with minute
red crystals of greenockite sprinkled on wavellite,
quartz, cassiterite or
marcasite, or as orange mamillary aggregares to 1 cm on
cassiterite and quartz, with
variscite and wavellite. The
greenockite appears to have been deposited hydrothermally as a late-stage
primary mineral
(Minrec 37.2.138).
Greenickite from Llallagua - Image
At the Guerrero mine, Taxco municipality, Mexico, greenockite has been found as coatings on
sphalerite
(Minrec 42.5.430).
At Tsumeb, Oshikoto region, Namibia, the zinc-cadmium sulphides of the
wurtzite-greenockite series were scattered through a
lead-rich,
zinc-deficient mineral assemblage containing moderate amounts of
pyrite, tennantite,
bornite, chalcocite and
digenite, within the cadmium bearing zone which appeared to have escaped
supergene effects (AM 42.184). Greenockite occurs
only in association with sphalerite between 140 and 200 metre depths
(R&M 93.6.545).
Greenockite from the Tsumeb Mine -
Image
The type locality is the Bishopton tunnel, Bishopton, Renfrewshire, Scotland, UK.
Greenockite from the Bishopton tunnel -
Image
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