Orange platy crystals of the very rare Ba-Ti-silicate mineral hejtmanite from one of the few localities known worldwide (Dara-i-Pioz Glacier, Tien Shan Mountains, Districts of the Republican Subordination, Tajikistan). — Photo: David Hospital · CC BY-SA 4.0
Hejtmanite
Hejtmanite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ba₂Mn²⁺₄Ti₂(Si₂O₇)₂O₂(OH)₂F₂.
It crystallizes in the monoclinic crystal system (space group P2_1/m). It is a member of the Seidozerite-Bafertisite structural group.
Key properties: specific gravity 3.97–4.06; Brownish yellow streak; Vitreous luster; optically biaxial.
IMA symbol Hej, IMA status: approved, named in 1989.
Found in arfvedsonite veins in pegmatite cutting alkalic granite and syenite (Mbolwe Hill, Zambia).
It is found associated with Manganoan arfvedsonite, albite, bastnÄasite, chevkinite, manganoan ilmenite, apatite, aegirine (Mbolwe Hill, Zambia).
The mineral was named to honor Dr. Bohuslav Hejtman, Emeritus Professor of Petrology, Charles University, Prague, Czech Republic.