The crystal structure of strontian potassicrichterite (Mg4.871Fe~+126Mno.052h5.049 (NaL425CaO.348SrO.297)r2.07Ko.873Si8.04802iOHhI5 - an unusual amphibole containing up to 3.7 wt.% SrO from the Murun alkaline massif, Eastern ...