AM_Bertrandite_1 Formula: Be4 Si2 O9 H2 Name: Bertrandite Unit cell: 8.7135 15.268 4.5683 90.0 90.0 90.0 , V=607.76 Space group: CMC21 (36)

Hazen R M , Au A Y , Physics and Chemistry of Minerals , 13 (1986) p.69-78, High-pressure crystal chemistry of phenakite (Be2SiO4), and bertrandite (Be4Si2O7(OH)2), Sample: P = 1 bar