Copper is a metallic compound that is highly conductive and corrosion resistant, which makes it an important material for electrical wiring and circuitry. Copper has also often been use to make decorative items and household wares such as vases, plates, cups and bowls. Copper is naturally a reddish-orange colored metal with a metallic luster. When copper has been exposed to air for many years it often has a green patina on the surface. So why does copper appear green after many years? Read on to find the answer.
Why does copper turn green?
The reason that copper turns green is the same reason the metal rusts, oxidization. Both metal and copper oxidize when exposed to oxygen and this is a natural process. Copper that is exposed to the outside environment is more likely to turn green and that is why copper vases and decorative pieces in gardens are often green.
Oxidization is a chemical process in which an element loses electrons over time. This changes the nature of the element and, in cases such as copper, the color. The green patina on the surface of copper is not corrosive and does not actually damage the metal, but acts as a protective coating. With other metals that rust the oxidization process actually damages the metal and makes it weaker and less cohesive.
Did you know?
The Statue of Liberty is not actually green! It is made from copper and it is the green patina that you see on the outside of the statue that gives it its green coloring.