Kaersutite is a dark brown to black double chain calcic titanium bearing amphibole mineral with formula: NaCa2(Mg3Ti4+Al)(Si6Al2)O22(OH)2.
Ferro-kaersutite iron rich endmember of the kaersutite group, with the iron replacing magnesium in the structure.
It occurs as phenocrysts in alkalic volcanic rocks and gabbro , monzonites. Mineral association includes titanian , rhoenite, plagioclase
It was first described in 1884 and is named for Qaersut (formerly Kaersut), Umanq