Ktenasite

minerals

namuwite

schulenbergite

langite

Formula: (Cu,Zn)5(SO4)2(OH)6.6H2O
Hydrated sulphate containing hydroxyl, ktenasite group
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).

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).

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).

At 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).

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).

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