Why does copper have many different colors?

Copper though is not widely used as iron and steel. But it has many advantages that iron and steel cannot match. Pure copper has extremely good electrical conductivity and heat transfer. In the technology of manufacturing electric machines, wires, etc., there must be a large amount of copper.

Red copper is a very pure metal, often using electrolytic methods of crude copper to manufacture.

Red copper is very soft, 1 drop of pure copper can last 2000m and can be laminated more than a sheet of paper, can even be transparent, the wind blows.

Brass is an alloy of copper and zinc. Brass is yellow depending on the zinc content of different copper colors. If the zinc content is 18% - 20%, the brass is red, 20% - 30% brown yellow, 30% - 42% light yellow, 50% - 60% transparent yellow. Brass used in industry often has a content of 45% or less of zinc.

Black copper is an alloy of copper and tin, sometimes with zinc, used to cast statues. There are many cold-faced metals that shrink, but the cold black copper expands. Black copper with high abrasion resistance should be used to make bearings.

Copper nickel alloy alloy is made into transparent copper used to make polished and non-rusty containers