ETYM French béryl, Old Fren. beril, Latin beryllus, Greek beryllos, prob. from Skr. vaidûrya. Related to Brilliant.
The chief source of beryllium; colored transparent varieties are valued as gems.
Mineral, beryllium aluminum silicate, Be3Al2Si6O18, which forms crystals chiefly in granite. It is the chief ore of beryllium. Two of its gem forms are aquamarine (light-blue crystals) and emerald (dark-green crystals).
Well-formed crystals of up to 200 tons have been found.

Beryllium

ETYM New Lat.
A light strong brittle gray toxic bivalent metallic element; SYN. Be, glucinium, atomic number 4.
Hard, white metal used in alloys, occurring as an element only in compounds.
Hard, light-weight, silver-white, metallic element, symbol Be, atomic number 4, atomic weight 9.012. It is one of the alkaline-earth metals, with chemical properties similar to those of magnesium; in nature it is found only in combination with other elements. It is used to make sturdy, light alloys and to control the speed of neutrons in nuclear reactors. Beryllium oxide was discovered in 1798 by French chemist Louis-Nicolas Vauquelin (1763–1829), but the element was not isolated until 1828, by Friedrich Wöhler and Antoine-Alexandre-Brutus Bussy independently.
In 1992 large amounts of beryllium were unexpectedly discovered in six old stars in the Milky Way.
The name comes from Latin beryllus.