Ktenasite

ktenasite

namuwite

schulenbergite

langite

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

Hydrothermal 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

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