Category Tectosilicate Strunz classification 9.FA.60 Space group Iba2 | Formula
(repeating unit) BaNa2Al4Si4O16 Crystal system Orthorhombic | |
Crystal class Pyramidal (mm2)
H-M symbol: (mm2) | ||
Banalsite is a rare barium, sodium aluminium silicate mineral with formula: BaNa2Al4Si4O16. Banalsite is a tectosilicate of the feldspar group.
Banalsite and its strontium analogue, stronalsite (SrNa2Al4Si4O16), constitute a complete solid solution series. In addition limited solid solution with calcium exists between these and lisetite: CaNa2Al4Si4O16.
It was first described in 1944 for an occurrence in the Benallt Mine, Rhiw, Llanfaelrhys, Lleyn Peninsula, Gwynedd (Caernarvonshire), Wales. The name is derived from the chemical symbols of its composition. It has also been reported from Långban, Värmland, Sweden and from the Kalahari manganese field, Cape Province, South Africa. It has recently been reported from the nepheline syenites of the Zhidoy massif, Eastern Sayan, Siberia, Russia; the Prairie Lake complex of alkaline rocks and carbonatites, Superior Alkaline Province, northwestern Ontario, Canada; the Pilansberg peralkaline complex, South Africa; the Sakharjok alkaline complex in the Kola Alkaline Province, Kola Peninsula of northwestern Russia {the Gremyakha–Vyrmes peralkaline complex, and the Turiy Mys complex of ultramafic–alkaline rocks and carbonatites.