Talk:Peridot/@comment-3965346-20150206224925/@comment-28584561-20150206231850

A lot of chemicals change color when exposed to air, heat, and other chemicals. Our blood turns brown due to oxidation; hemoglobin in our blood contains iron, which gives it its red color, when exposed to air, the iron forms bonds with the oxygem present in air, producing iron oxide, which has a brown color. The closest thing you could compare it to with your blood theory is the blood of molluscs and crustaceans, which contain hemocyanin. Hemocyanin contains copper (as opposed to hemoglobin containing iron), copper in the blood is either colorless to grey-white but when exposed to air, it makes bonds with oxygen and turns blue hence the name hemocyanin