The name of beryllium is derived from the Greek word for beryl, beryllos. It is based on the fact that beryllium is a component of the mineral, which was known as beryl before the element's discovery. Beryllium was discovered in 1797 by Nicolas Louis Vauquelin.
Pure beryllium is a gray metal solid at room temperature. It has an atomic number of 4 and an atomic symbol of Be. The mineral beryl is comprised of the compound beryllium aluminum silicate. The gems emerald and aquamarine come from this mineral. Beryllium is transparent to X-rays, making it useful in the production of X-ray windows. When alloyed with copper, beryllium is used to make wear-resistant devices such as gyroscopes.