### Theory:

Copper
Copper is the first metal known and used by man. After Iron and Aluminium, Copper ranks as the third most consumed industrial metal in the world. Copper is a good conductor of heat and electricity. Therefore, a significant amount of the metal (about $$75%$$of copper) is used in making wires, telecommunication cables and electronics.

Chile is the world’s largest producer of copper. Other copper-producing countries are Peru, China, United States, Congo and Australia.
Ores of copper: Chalcopyrite, Chalcocite, Covellite
Gold
Gold is a dense lustrous yellow, rare and precious metal. Compared to other metals, gold is less chemically reactive. In the world market, it has exceptional value and high demand. Earlier, it was used in minting coins, but now, it is used to make ornaments and in dentistry due to its high malleability. It is considered a symbol of prosperity and form of wealth. It is also used as a medium of exchange to some extent.

China is the world’s largest producer of gold. Other major producers of gold are Australia, Russia, United States, South Africa and Canada. Among these countries, Australia is the world's leading country in gold ore reserves, with $$9500 tons$$reserves of gold ore. Karnataka is the largest producer of gold in India. Kolar Gold Field in Karnataka is one of the deepest mines in the world.