Silver Plated Pyrite BraceletSilver Plated Pyrite Bracelet Note Pyrite naturally oxidizes with time, so its pale metallic shine can slowly darken or change. Even the U. S. Geological Survey (USGS) mentions that pyrite reacts with oxygen and ferric iron, gradually changing through oxidation. So this slight change in appearance is actually a sign of natural, genuine pyrite. Thats why if a stone stays extremely bright yellow or golden for years without any visible change at all,