Beryl in its purest form is completely colorless (goshenite). Trace impurities and coloring agents are responsible for the many different colors found in gemstone varieties of beryl. Beryl is one of the most important mineral groups and also one of the biggest gemstone groups. Although the mineral is abundant, it rarely occurs in transparent gem-quality material. Transparent gem-quality beryl is referred to as 'precious beryl'. The most famous beryl gemstone is green emerald, followed by blue aquamarine. Golden beryl is not very well-known by the general public. Other popular beryl gems include pink 'morganite' and white, or colorless, 'goshenite'. Red beryl is the rarest variety of beryl and it is known in the trade as 'bixbite'.