The Mineral Chalcoalumite

Chalcoalumite is a monoclinic-sphenoidal (Monoclinic is one of point groups in the 7 lattices, and Sphenoidal means an improperly developed by-pyramid prism having corners that are wedge shaped) mineral that contains Copper, Aluminum, Oxygen, Hydrogen and Sulfur. Its ionic (an ion that is charged negatively and travels during electrolysis to the anode) interlayer may replace sulfate groups with Sb (OH)- 6 groups.

Chalcoalumite demonstrates various colors like blue, bluish gray, light bluish green and greenish blue. Its lucidity varies from transparent to translucent and has perfect cleavage. The mineral possesses a glass-like dull luster, having a streak of bluish white. Characteristically twinned on {100}, acquiescent composites are very much like bulky untwined individuals. Twinning on {010} results in the formation of tablets in the shape of diamonds. Twinning on {136} results in a swallowtail compound having deep reentrant or fourlings (A twin crystal or compound comprising four individuals) and eightlings. Diamond-shaped eight lings with all the three twin laws have also been recorded.

Chemical Formula
CuAl4 (SO4)(OH)12 .3H2O

Derivation of Name
The mineral Chalcoalumite derived its name from the Greek word chalkos, implying “copper," and for its aluminum content, or probably because of the aluminum sulfate compound it contains, people sometimes refer to as a kind of alum.

Occurrence
Chalcoalumite is a rare secondary mineral found in oxidized parts of copper deposits. It is frequently coupled with minerals like Azurite, Cuprite, Goethite, Hydrombobomkulite, Mbobomkulite and Malachite.

Gemology
Chalcoalumite is not used as gemstones.

Source
This mineral is found in the United States, Wales, Belgium, Canada, England, Italy, Sweden, Slovakia, South Africa, and Wales etc.

Mineralogy
As per the Chalcoalumite mineral data, it is an excellent botryoidal (external form resembling a bunch of grapes) with light sky blue color. Its layers are certainly found in attached cavities of the Copper Queen Mine, Bisbee, USA. A number of smaller cavities also contain Chalcoalumite. The other minerals associated with it include Azurite in royal blue color and Malachite in green color. The deposits of this secondary minerals are very rare and get formed by replacing laths (thin, narrow strips) of devilline (a sulfate mineral) on joints in veinstone as a white substitute of both a Tyrolite-Like Mineral and Malachite

Color
It comes in bluish gray, pale blue, turquoise-green color and is colorless in transmitted light.

Density 
2.29 g/cm3

Hardness (Mohs Scale):
2.5

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