Byzantievite
Byzantievite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ba₅(Ca,REE,Y)₂₂(Ti,Nb)₁₈(SiO₄)₄[(PO₄),(SiO₄)]₄(BO₃)₉O₂₂[(OH),F]₄₃(H₂O)₁.₅.
It crystallizes in the hexagonal crystal system (space group R3).
Key properties: Mohs hardness 4.5–5; specific gravity 4.1; Pale yellow streak; Vitreous to slightly greasy on fracture surfaces luster; optically uniaxial.
IMA symbol Byz, IMA status: approved, named in 2009.
Found in a glacial moraine boulder of coarse-grained alkaline igneous rock.
It is found associated with Quartz, microcline, aegirine, zircon, thorite, calcybeborosilite-(Y), pyrophanite, titanite, nalivkinite, stillwellite-(Y), danburite, pyrochlore.
The name refers to the Byzantine Empire, in allusion to the complexity, effectiveness and beauty this mineral’s atomic structure shares with this empire that existed for nearly 12 centuries.