The Mineral KTENASITE

Chemistry: (Cu, Zn)₅(SO₄)₂(OH)₆ - 6H₂O, Hydrated Copper Zinc Sulfate Hydroxide.
Class: Sulfates.
Uses: As a very minor ore of copper and zinc and as mineral specimens.
Specimens

Ktenasite is a rare mineral from the classic mineral site at Laurium, Attiki, Greece. Ktenasite is a colorful mineral. It is often associated with other colorful minerals such as serpierite, glaucocerinite and smithsonite. Ktenasite forms crusts of lovely blue-green aggregates and tiny crystal rosettes adorning other minerals. Ktenasite forms as the result of the oxidation of copper and zinc sulfide minerals.

PHYSICAL CHARACTERISTICS:

Color is blue-green to green.
Luster is vitreous.
Transparency: Specimens are translucent to transparent.
Crystal System is monoclinic.
Crystal Habits include small tabular crystals that can form rosettes and encrusting masses.
Cleavage is poor but discernible.
Fracture is uneven.
Hardness is 2 - 2.5
Specific Gravity is approximately 2.9 - 3.0 (average for non-metallic minerals).
Streak is pale green.
Associated Minerals include serpierite, glaucocerinite, smithsonite, pyrite, chalcopyrite and gypsum.
Notable Occurrences include the Kamaresa Mine, Laurium, Attiki, Greece; Norway and in the USA at sites in Colorado as well as at Bisbee and the 79 Mine of Arizona.
Best Field Indicators are crystal habit, color, associations and locality.