A form of heat treatment for sapphire that adds the element beryllium to the heating process. Beryllium is an element well known in the gem world, since it is an essential constituent in many gemstones, including emerald, beryl, and aquamarine. When sapphires are heated with beryllium, the result is a reduction in blue tones. Thus bright yellow or orange sapphire can be produced from weak yellow or greenish gems. Some stunning colours have been produced using this method.