Formula: (Cu,Zn)5(SO4)2(OH)6.6H2O
Hydrated sulphate, ktenasite group
Crystal system: Monoclinic
Specific gravity: 2.94
Hardness: 2 to 2½
Streak: Light green
Colour: Blue-green
Solubility: Soluble in dilute acids and ammonia (Dana)
Environments
Ktenasite is an uncommon secondary mineral formed by
oxidation of chalcopyrite and
sphalerite in copper-zinc hydrothermal mineral deposits and in mine dumps.
Associated minerals include glaucocerinite,
serpierite, smithsonite,
gypsum, namuwite and
schulenbergite
(HOM).
Localities
At Kintore, Broken Hill, New South Wales, Australia, ktenasite was quite common on the dumps, occurring as
thin crusts and fibrous intergrowths with langite and other minerals.
Serpierite is often seen with ktenasite and the most common matrix
is an etched quartz-rich rock containing small patches of
chalcocite. In block 14 ktenasite has been found with
linarite, brochantite and
azurite, and also as crusts in fractures in
mica schist
(AJM 3.1.43).
Ktenasite from Kintore - Image
At the type locality, the Jean Baptiste Mine, Kamariza Mines, Lavrion mining district, Lavreotiki, Attica, Greece,
ktenasite has been found associated with glaucocerinite and
serpierite in smithsonite
(Dana). One specimen consists of porous smithsonite with a thin
crust of glaucocerinite
(AM 36.381-382).
Ktenasite from the Jean Baptiste Mine -
Image
At Glomsrudkollen, Modum, near Drammen, Norway, platy crystals of ktenasite to 1 mm have been found on
sphalerite, with small crystals of
gypsum (AM 64.446-448). It is also associated with
gypsum and bianchite, on a
breccia of rock and mineral fragments. The primary sulfides present
are sphalerite, pyrite and
chalcopyrite
(JRS 4.13-15).
Ktenasite from Glomsrudkollen - Image
At Smallcleugh and Brownley Hill mines, Nenthead, Cumbria, England, UK, a small suite of specimens collected underground
contain grains of ktenasite.
Gypsum covers most samples and tiny crystals of ktenasite are
included in it. Smithsonite is finely disseminated throughout some
gypsum-bearing regions of the specimens
(JRS 4.13-15).
Ktenasite from the Smallcleugh Mine -
Image
At the Commodore mine, Creede, Colorado, USA, ktenasite has been found coating
chalcopyrite and sphalerite
crystals. In some specimens ktenasite encrusts only chalcopyrite,
leaving adjacent sphalerite uncovered. Associated accessory minerals
include quartz, galena,
anglesite and powdery coatings of
goslarite
(AM 64.446-448).
Ktenasite from the Commodore Mine -
Image
Back to Minerals