Abstract
The existence of lonsdaleite in meteorites was checked by examining 120 carbon-rich grains from 10 ureilites by an x-ray diffraction method using a Gandolfi camera. Some carbon-rich grains accompanying compressed graphite with the smallest basal-spacing shows an x-ray powder diffraction pattern similar to that assigned to lonsdaleite by Hanneman et al.(1967). The results of this study reveal that the mineral showing a similar pattern to that of Hanneman et al. (1967) may be a disordered diamond and therefore lonsdaleite can not be found in meteorites in this study.
