Copper is a chemical element with symbol Cu (from Latin: cuprum). It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; a freshly exposed surface has a reddish-orange color. It is used as a conductor of heat and electricity.
Copper is considered to be the first metal that man used for the construction of utensils, tools and guns. It is estimated that it is discovered at 9000 BC in the Middle East.
The metal and its alloys have been used for thousands of years. In the Roman era, copper was principally mined on Cyprus, hence the origin of the name of the metal asсyprium (metal of Cyprus), later shortened to сuprum

Brass is an alloy made of copper and zinc. It has a yellowish-golden color. It is used from the Hellenistic ages till today for the construction of tools, guns, statues (Charioteer of Delphi, Statue of Liberty), decorative utensils and wind musical instruments.

Nickel is a chemical element with symbol Ni. It is a silvery-white lustrous metal. It is hard like iron and ductile. The metal of nickel is slow to react with air at ambient conditions due to the formation of a protective oxide surface.

Tin is a chemical element with symbol Sn. It is not easily oxidized in air and is used to coat other metals to prevent corrosion. Tin is a malleable, ductile and highly crystalline silvery-white metal. It has antimicrobial and nonstick action.