"Beril" and "Heliodor" redirect here. For the character in Tolkien's legendarium, see House of Bëor. For the given names, see Beryl (given name) or Heliodorus (given name). For the Sailor Moon villain, see Queen Beryl. For other uses, see Beryl (disambiguation).In geology, beryl is a mineral composed of beryllium aluminium cyclosilicate with the chemical formula Be3Al2Si6O18. The hexagonal crystals of beryl may be very small or range to several meters in size.