Post by Admin on Sept 18, 2023 9:55:33 GMT -7
Copper crystalizes in the cubic system. It has a metallic luster, is heavy with a specific gravity of 8-9 with a hardness of 2-1/2 to 3 so it can be easily scratched with a knife. Copper has no cleavage, is ductile and malleable. Its fracture is hackly. It is copper red on fresh fracture but may be greenish or bluish or tarnished if weathered. It is often found with small amounts of arsenic, antimony, bismuth,iron, gold and silver.
Copper Ores
Azurite also is a copper carbonate. Itís streak is light blue. Malachite and azurite frequently occur together and are found in the upper weathered (oxidized) zones of copper ore bodies. Azurite is the scarcer of the two has a soft blue color.
Bornite is a copper-iron sulfate. Its color is a natural bronze, but on exposure it tarnishes to the varigated colors that have caused it to be nicknamed ìPeacock ore.î It is rarely found on the surface but is prevalent in deeper levels of copper mines.
Chalcocite is a copper sulfate. It is one of the highest grade and most important ores of copper and is opaque with a dark lead gray to black color. Chalcocite is often associated with and shows alteration to azurite, bornite, covellite, malachite, and native copper. Important deposits are found in Arizonaís Bagdad, Jerome, and Superior areas. Other localities include Bingham, Utah; Santa Rita, New Mexico; Ely, Nevada, and the Genesee Valley district in California.
Chalcopyrite is an iron-copper sulfide. It has a brass yellow color. It is distinguished from pyrite by being softer and yellower. Its golden glint when in small specks in quartz often is mistaken for gold. The glint will disappear when turned at certain angles to the light while gold appears the same at all angles. Chalcopyrite is the primary ore of copper and is prevalent wherever copper ore is being mined below the surface zone.
Chrysocolla has various shades of blue to green and is a hydrous copper silicate. It is often found with azurite and malachite. Although its color is attractive, it is too soft to make good gem stones. Be aware of this fact when buying jewelry. Sometimes chrysocolla is passed off as turquoise.
Malachite (pronounced mala-kite) is usually a bright green color and has a nonmetallic luster. It has a light green streak and can always be scratched with a knife. Malachite, a copper carbonate, is an important ore of copper and is a good indicator of copper deposits. In its pure form it contains 57% copper, the rest is made up of carbonate and water.
Turquoise is a hydrous aluminum phosphate with copper. To be desirable for gems the color should be green blue. The color is due to the presence of copper and is found near the surface of copper deposits. Sometimes in may appear as an outcrop.