It used to be a dull brown due to copper plates but slowly turned green. A weathering process known as oxidation occurred when air and water reacted with the copper that makes up the statue of liberty.
because, it used to be an entire statue of brown copper, but now it has a green tint to it. Lemme explain it this way. Have you ever seen a penny that’s a little green-whiteish? Well thats what happened to the statue. Hth!
