Blocky,
red crystals of Cuprite in a stalactitic mass of Limonite from the Ray Mine near
Winkleman, Arizona.
A close up view of the above Cuprite specimen from Winkleman, AZ. This
photo shows the cubic nature of the crystals.
Octahedral crystals of Cuprite.
A common occurrence of
massive Cuprite with associated malachite and azurite.
Cuprite
crystals replacing Copper crystals. The shape of the large mass on the
right is that of a Copper crystal that has chemically altered to produce a Cuprite coating.
This specimen is also from the Ray Mine in Arizona.
Chalcotrichite is the fibrous
variety of Cuprite.
CHEMISTRY Cu2O Copper oxide
CRYSTALLOGRAPHY Isometric (Cubic)
CRYSTAL GROWTH AND HABITS Cuprite forms as cubes, octahedrons or dodecahedrons and commonly forms as elongate crystals. It is also found as compact granular masses. The finely fibrous red crystals are referred to as Chalcotrichite.
COLOR AND OTHER OPTICAL PROPERTIES Red to nearly black
HARDNESS 3.5 - 4
SPECIFIC GRAVITY 5.8 - 6.1
LUSTER Adamantine to submetallic
STREAK Brownish red
BREAKABILITY Brittle
OCCURRENCE Cuprite is found in the oxidized zone of copper deposits.
ASSOCIATED MINERALS Copper, Azurite, Malachite, Brochantite