Discovery of Meteoritic Lakargiite (CaZrO₃), a New Ultra-Refractory Mineral from the Acfer 094 Carbonaceous Chondrite

During a nano-mineralogy investigation of the Acfer 094 carbonaceous chondrite, lakargiite (CaZrO₃) was identified as submicrometer inclusions in an isolated hibonite grain in section USNM 7233-1. The hibonite grain is described in Simon and Grossman [1]. Lakargiite is a recently found perovskite-group mineral from hightemperature skarns in ignimbrites of the Upper-Chegem volcanic structure, the North Caucasus, Russia [2]. Reported here is the first extraterrestrial occurrence of lakargiite, as a new ultrarefractory mineral in a primitive meteorite, among the first solids formed in the solar system. Field-emission SEM with EDS and electron back-scatter diffraction (EBSD) was used to characterize its composition and structure and associated phases.