Paperweights must have first appeared along with paper in ancient Egypt. It is said that glass paperweights first appeared at an 1845 industrial exposition in Vienna. Today's collectors search for every type, from the very expensive French weights of the nineteenth century to the modern artist weights or advertising pieces. The glass tops of the paperweights sometimes have been nicked or scratched, and this type of damage can be removed by polishing. Some serious collectors think this type of repair is an alteration and will not buy a repolished weight; others think it is an acceptable technique of restoration that does not change the value. Baccarat paperweights are listed separately under Baccarat.