banalsite

{{infobox mineral | name = Banalsite | category = Tectosilicate minerals | group = Feldspar group | image =Banalsite.jpg | alt = | caption = Banalsite from Sweden (brown) on matrix | boxbgcolor = #231709 | boxtextcolor = white | formula = BaNa2Al4Si4O16 |IMAsymbol=Bns | IMAstatus = Grandfathered (1944) | molweight = | strunz = 9.FA.60 | dana = 76.1.6.1 | system = Orthorhombic | class = Rhombic pyramidal (mm2) | symmetry = Iba2 (no. 45) | unit cell = a = 8.496(2) Å, b = 9.983(2) Å, c = 16.755(3) Å; Z = 4 | color = White, brown | colour = | habit = Rarely showing traces of crystal faces; coarsely crystalline to compact, massive | twinning = | cleavage = Good on {110} and {001} | fracture = | tenacity = | mohs = 6.5 | luster = Vitreous, pearly on cleavage | streak = White | diaphaneity = Translucent to transparent | gravity = 3.065 | density = | polish = | opticalprop = Biaxial (+) | refractive = nα = 1.570 nβ = 1.571 nγ = 1.578 | birefringence = | pleochroism = | 2V = Measured: 41°, Calculated: 52° | dispersion = | extinction = | length fast/slow = | fluorescence= | absorption = | melt = | fusibility = | diagnostic = | solubility = | other = | alteration = | references = }} 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.