Ba-Fe titanates in peralkaline granite of the Ilimaussaq Complex, South Greenland

A peralkaline granite of the Ilimaussaq Complex, South Greenland, contains the rare mineral henuymcyerite [(Ba0.92Na0.05Ca0.03)(1.0)(Ti6.87Fe1.042+Nb0.03)(7.9)O-16], a low-Fe Ba titanate [(Ba0.74Ca0.02Na0.05)(0.8) (Ti4.90Fe0.152+Nb0.04)(5.1)O-11], and an unidentified Ba titanosilicate. Both titanates show the coupled substitution 2Na(+) + Si4++ -> Ba2++ Ti4+. The minerals are present as tiny crystals fringing ilmenite inclusions in an amphibole crystal and are thought to have formed during the hydrothermal stage of the granite's evolution.