Mirrors are another type of glass that has its own unique properties. Mirrors are unique because of their highly reflective surface. Mirrors are made differently depending on the type of mirror that it is.
Most commonly one will find what is called a one-way mirror. One-way mirrors have only one side that is reflective. One-way mirrors are made with a sheet of metal, usually aluminum, which is polished intensely and then covered with plate glass. The plate glass placed on the metal of a one-way mirror is used as a protective cover and a way to keep the polished metal from becoming less reflective.
Another type of mirror is called a two-way mirror. Two-way mirrors are made only of glass, they work as a mirror for the side that has more light on it; the more light on one side means more light is reflected by the glass. Two-way mirrors are often used in interrogation rooms. The usefulness of them is that on one side a person can’t see through them where on the other the people can see straight through.