Copper Ore and Stone
Copper is a chemical element with the symbol Cu (from Latin:
cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with
very high thermal and electrical conductivity. A freshly exposed surface of
pure copper has a pinkish-orange color. Copper is used as a conductor of heat
and electricity, as a building material, and as a constituent of various metal
alloys, such as sterling silver used in jewelry, cupronickel used to make
marine hardware and coins, and constantan used in strain gauges and
thermocouples for temperature measurement.
Copper is one of the few metals that can occur in nature in
a directly usable metallic form (native metals). This led to very early human
use in several regions, from c. 8000 BC. Thousands of years later, it was the
first metal to be smelted from sulfide ores, c. 5000 BC, the first metal to be
cast into a shape in a mold, c. 4000 BC and the first metal to be purposefully
alloyed with another metal, tin, to create bronze, c. 3500 BC.
In the Roman era, copper was principally mined on Cyprus,
the origin of the name of the metal, from aes сyprium (metal of Cyprus), later
corrupted to сuprum (Latin), from which the words derived, coper (Old English)
and copper, first used around 1530.
The commonly encountered compounds are copper (II) salts,
which often impart blue or green colors to such minerals as azurite, malachite,
and turquoise, and have been used widely and historically as pigments.
Copper used in buildings, usually for roofing, oxidizes to
form a green verdigris (or patina). Copper is sometimes used in decorative art,
both in its elemental metal form and in compounds as pigments. Copper compounds
are used as bacteriostatic agents, fungicides, and wood preservatives.
Copper is essential to all living organisms as a trace
dietary mineral because it is a key constituent of the respiratory enzyme
complex cytochrome c oxidase. In molluscs and crustaceans, copper is a
constituent of the blood pigment hemocyanin, replaced by the iron-complexed hemoglobin
in fish and other vertebrates. In humans, copper is found mainly in the liver,
muscle, and bone. The adult body contains between 1.4 and 2.1 mg of copper per
kilogram of body weight.