The Datolite Group of Minerals

The Datolite Group (which is also known as the Datolite/Gadolinite Group after its two most common members) is composed of similarly structured nesosilicates. Its members contain alternating borate tetrahedrons, B(O, OH)₄, and silicate tetrahedrons, SiO₄, that are connected to each other in a sheet like structure. Between the tetrahedral sheets and linking the tetrahedral sheets are metal cations in 8 coordination. Dispite the layered structure, cleavage is all but completely absent. Some members have beryllium instead of boron in the non-silicate tetrahedrons. Several members have rare earth metals as part of their compositions. The general formula for the Datolite Group is approximately: X(B, Be)SiO₄(OH, O). The X ion can be either calcium, magnesium, cerium, lanthanum, iron, tin, niobium, yttrium, ytterbium and/or erbium.

• Datolite (Calcium Boro-Silicate Hydroxide)
• Bakerite (Hydrated Calcium Boro-Silicate Hydroxide)
• Gadolinite-(Ce) (Cerium Lanthanum Niobium Yttrium Iron Beryllium Silicate)
• Gadolinite-(Y) (Yttrium Iron Beryllium Silicate)
• Hingganite-(Ce) (Cerium Yttrium Iron Beryllium Silicate Hydroxide)
• Hingganite-(Y) (Yttrium Ytterbium Erbium Beryllium Silicate Hydroxide)
• Hingganite-(Yb) (Ytterbium Yttrium Beryllium Silicate Hydroxide)
• Homilite (Calcium Iron Magnesium Boro-Silicate)
• Minasgeraisite-(Y) (Calcium Yttrium Beryllium Silicate)
• Vistepite (Manganese Tin Boro-Silicate )
• Yttroceberysilite (Yttrium Boron Beryllium Silicate )