Bulgakite
Bulgakite is an IMA-recognized mineral species in the silicate class, with the chemical formula Li₂(Ca,Na)Fe²⁺₇Ti₂(Si₄O₁₂)₂O₂(OH)₄(O,F)(H₂O)₂.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Astrophyllite-Astrophyllite structural group.
Key properties: Mohs hardness 3; specific gravity 3.3; Pale brown streak; Vitreous luster; optically biaxial.
IMA symbol Bgk, IMA status: approved, named in 2014.
Found in fenitized amphibole-quartz-feldspar rock from a complex alkaline massif.
It is found associated with Alkali amphibole, quartz, microcline, bafertisite, aegirine, calcybeborosilite-(Y), thorite, fluorite.
The mineral was named to honor Lev Vasil’evich Bulgak (b. 1938), Russian mineralogist, gemologist, translator of geological literature.