A translucent or opaque mineral composed of a silicate of aluminum and beryllium. It is harder than quartz and is usually yellow green, but sometimes it is green, yellow, blue, white, pale red, or colorless. Dark-green beryl is classed as emerald, the blue-green is aquamarine, and the rose variety is called morganite. Beryl is found normally in granitic rocks in the form of six-sided crystals. Individual beryl crystals weighing over 25 tons have been discovered.

Beryl was a very popular gemstone in ancient times. The Greeks made fine intaglios from it, and the Romans worked the natural crystals into ear pendants. Beryl (Gr., beʹryl·los) is mentioned once in the Scriptures (NW, NE, RS), it being the eighth foundation of the wall of New Jerusalem.​—Re 21:2, 19, 20.