Bertrandite is a beryllium sorosilicate hydroxide mineral with composition: Be<sub>4</sub>Si<sub>2</sub>O<sub>7</sub>(OH)<sub>2</sub>. Bertrandite is a colorless to pale yellow orthorhombic mineral with a hardness of 6–7.
It is commonly found in beryllium rich pegmatites and is in part an alteration of beryl. Bertrandite often occurs as a pseudomorphic replacement of beryl. Associated minerals include beryl, phenakite, herderite, tourmaline, muscovite, fluorite and quartz.
See also
- List of minerals
- List of minerals named after people