As the name of the material would suggest, the statue was originally a 
bright copper color. However, once she was assembled in New York 
harbor, a reaction called oxidation—which is also responsible for rust—
began. Her copper exterior began to react with the oxygen in the air.
That reaction created tenorite, a dark brown-black material. So her 
copper color got darker before it got lighter.
 Completing the chemical makeover, sulfuric acid in 
the air (much of which comes from New York air 
pollution) reacted with the tenorite and the 
oxidized copper, turning the exterior green. By 1906, 
all traces of copper were gone and the statue was 
the color we know today. However, in the early 1900s,
Congress collected money for repairs, suggesting 
that the statue be painted its original copper color—
but people protested, and the “repairs” never 
happened. Thankfully, because we certainly can’t 
imagine this iconic statue being any other color. 
But with all of these reactions, will the Statue of Liberty be changing her
color again anytime soon? Will we see a purple Statue of Liberty? Luckily,
no. The statue’s exterior is finally “stable,” meaning it’s not reacting 
anymore. Green will continue to stand for liberty for generations to come.