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Cuprite
Chemical composition -- Copper oxide.
Color -- Intense red, brownish red, or purplish red.
Scientific name comes from the Latin "cuprum", meaning copper. It's nickname is "ruby copper" from old miners. Pseudomorphs of malachite after cuprite a fairly common.
Photos
& Locals:
1.) Kolwezi-Shaba, Zaire
2.) Kolwezi-Shaba, Zaire ...
Commonly called "ruby copper", cuprite is a secondary ore of copper that occasionally forms attractive ruby-like transparent crystals. Cuprite has a high refractive index which is even greater than diamond.
Cuprite var. Chalcotrichite
Morenci
Cuprite var. Chalcotrichite - Old Paris Labels, 6.0cm x 8.7cm
Azurite - 5.0cm x 4.0cm
Cuprite var. Chalcotrichite - Former collections of Gerald Herfurth, E.M Gunnell, 4.0cm x 5.5cm ...
hematite
cuprite...
Sulfate, chromates, molybdates, wolframates
crocoïte...
cuprite ... copper oxide
Crystallography: isometric
Colors: ruby red
Luster: adamantine
Hardness: 3.5 - 4
Specific gravity: 5.8 - 6.2
Crystal or stone size: rare crystals have been cut as gems
Comments: ore of copper
Chert ... see quartz ...
Examples of such species include zincite (ZnO), tenorite (CuO), cuprite (Cu2O), rutile (TiO2), uraninite (UO2), corundum (Al2O3), hematite (Fe2O3), and magnetite (Fe3O4).
(Cuprite var. Chalcotrichite)
Carbonates - Minerals containing the carbonate (CO3) radical as a major component. (Calcite)
Cleavage - Planes in a crystal which are easily split.
Aragonite, Aurichalcite, Azurite, Ankerite, Annabergite, Anglesite, Azurite, Beudantite, Brochantite, Cassedanneite, Cotunnite, Crocoite, Chrysocolla, Chlorite, Copper, Covellite, Calcite, Cuprite, Caledonite, Cerussite, Cobaltite, Chalcopyrite, ...
Older mineral textbooks state that this is a rare form, sometimes reported on cuprite. But most recent textbooks indicate that a restudy of cuprite's crystallography showed cuprite to probably be hexoctahedral.
Hey wait a minute, you say--> cuprite is red, malachite is green, and both contain copper! What gives? Welcome to the wonderful world of gem color! It is not quite as simple as: this element makes this color, and that element makes another color.
It is also found in various ores such as chalcopyrite, chalcocite, cuprite, and malachite. When alloyed with tin it forms bronze, and when alloyed with zinc it forms brass.
Minerals like magnetite, chromite, franklinite, spinel, pyrochlore, cuprite, gold, and diamond fall in this group.
DODECAHEDRON:
Magnetite and sodalite are placed in this category.
Malachite occurs in association with azurite, cuprite, and kaolinite, and there is a relatively rare, speckled variety of azurite-malachite which combines both minerals in a dramatic display of color.
Many beautiful specimens of Malachite contain other Minerals, such as Azurite, Cuprite or Chrysocolla. Malachite can be found in Zaire, USSR, Germany, France, Chile, Australia, Arizona and New Mexico/USA.
Rudabanya in Hungary also keeps us dreaming, with just so few malachite pseudomorphs after cuprite - just enough to whet the apatite (see photo).
In fact, the name, azurite, comes from the Arabic word for blue. A rarer Azurite mixture, known as "Bluebird", is Azurite mixed with dark red Cuprite.
It often occurs with malachite, chrysocolla or turquoise in areas with copper deposits. A rare form called "Bluebird", has dark red Cuprite mixed with azurite - notice the triangular shaped stone in the bottom left of the collage.
Associations:
Found associated with mafic volcanic rocks, formed by reaction between Cu-bearing solutions and Fe-bearing minerals. Associated minerals are cuprite, chalcocite, bornite, epidote, calcite, chlorite and zeolites.
A secondary copper mineral, malachite is a popular gem that has light and dark vivid green bands. Many beautiful specimens of malachite contain special combinations with other minerals, such as azurite, cuprite or chrysocolla.
Legends and lore ...
99, spessartite garnet, specific gravity of 4.15, marcasite, specific gravity of 4.9, and cuprite (s.g., 6.0) and casseterite (s.g., 6.9). Diamond is in the heavy mid-range, with a specific gravity of 3.52.
 See also: Crystal, Copper, Mineral, Minerals, Color
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