The Statue of Liberty is one of the most recognizable landmarks on the planet. If you were asked to describe it, one of the first things you’d likely mention (after the torch and hat, of course) would be its distinctive blue-green color.
But it wasn’t always this color. As a new video from the American Chemical Society explains, the original color of the Statue of Liberty has changed since it was gifted to the US by France in 1885. It was originally a rather magnificent copper.
“In her first few decades in the Big Apple, the statue slowly turned from that shiny copper color to a dull brown and then finally to the blue-green, or as they say back in France, ‘verdigris’, that we see today,” the American Chemical Society explains in their video.
The color change is the result of oxidation and air pollution. It wasn’t just one reaction that caused this particular shade, but a combination of reactions over the years. The first color change occurred when the copper on the statue reacted with oxygen in the air. The copper gave up electrons to the oxygen, leading to the mineral cuprite, which is a pinkish red.
After that, the cuprite gave up more electrons to oxygen, forming tenorite, which is black, causing the statue to become darker still. But, of course, it didn’t end there.
The water in the atmosphere, when mixed with sulfur, turns to sulfuric acid. When this was mixed with copper oxides on the statue, it began to turn its distinctive green color. Chloride from the sea spray added to this, making the statue even greener.
The statue has remained this color for over 100 years because the exposed copper is now chemically stable, but underneath that layer, it is still the original bronze. It’s likely to remain this shade of green now that the outside is fully oxidized.
When it was suggested that the color be restored to the original copper shade, the public protested the move, as they were now used to the iconic blue-green shade.