Silver (Ag), gold (Au), and copper (Cu) are metallic elements. Each of these metals have been used to make sculptures and jewelry for thousands of years. Bronze, steel, and brass are all alloys that artists often work with because of their durability and color. Iron and carbon make up steel. Bronze is a mixture of copper and tin. Zinc and copper make up brass. Coins, jewelry, and sculptures are all made up of alloys.
Metals can be damaged when exposed to the environment or to chemicals. A great example is the Statue of Liberty, a copper statue, that has turned blue-green. The reason is because the copper in the statue in the statue oxidized from years of exposure to humidity and other elements. The copper compounds formed as a result of this is a blueish-greenish color. This is also the case with old pennies.