Notable gemstones which contain beryllium include Beryl (Aquamarine, Emerald) and Chrysoberyl.
As a free element it is a steel-gray, strong, lightweight and brittle alkaline earth metal.
Tools made of beryllium copper alloys are strong and hard and do not create sparks when the strike a steel surface, six times stronger than copper alone.
Because of its low density and atomic mass, beryllium is relatively transparent to X-rays, and other forms of ionizing radiation (gamma rays).
Is a steel gray and hard metal that is brittle at room temperature.
Beryllium is non-magnetic.
Thin plates of beryllium used in nuclear weapon designs as the very outer layer of the plutonium pits.
