Oxidation is a chemical reaction named after the oxygen compound oxide. In many cases, oxygen is the trigger or participant of an oxidation, but oxidation is also possible without this element. This is the conversion of one chemical compound into another. The basic principle is always the same - electrons are given off by one substance and then taken up by another. This changes the chemical starting material, as can be explained using the example of iron. Exposure to air and water causes oxidation, which leads to rust. This rust makes the starting product vulnerable and porous. But oxidation also causes discoloration of jewelry. Especially costume jewelry, which often consists of base metals and is only coated with a thin layer of a precious metal, discolors over time. But precious metals such as silver or low gold alloys can also discolor. Compared to oxidation, however, there are also oxygen compounds that have the opposite effect. So there are metals that become more resistant when they oxidise. This process is called anodising and is done deliberately to provide metals such as aluminum or chrome with a protective coating.
