Clades:
Sorosilicates.
Chemical: Be4Si2O7(OH)2.
Crystal system: Orthorhombic.
Color: colorless to pale yellow.
Hardness: 6 to 7.
Region: Nantes, France; Spor Mountain, source of most of the world's berylliumHabitat: in beryllium rich pegmatites.
MineralogyBertrandite is a beryllium sorosilicate hydroxide, an alteration of beryl.
Associated minerals include beryl, phenakite, herderite, tourmaline, muscovite, fluorite and quartz.