Fig. 1.

Images of graphite, lonsdaleite, and diamond in ureilites. (A) Reflected light image showing folded crystalline graphite, with fold morphology defined by graphite cleavage (SI Appendix, Fig. S1). Different shading in the graphite is produced by axial planar kink bands. (B) Reflected light image (stacked foci) showing an example of the inherited fold morphology preserved in lonsdaleite (SI Appendix, Fig. S4). (C) CL map of the same area as (B) indicating different phases of carbon, where the green regions (from a fit of the 2.317 eV peak; SI Appendix, Fig. S3) are lonsdaleite and the red areas (from a fit of the 2.157 eV peak) on the periphery (including the purple dashed circle) are cubic diamond (blue is the CL response from olivine). (D) Scanning TEM Image of a region cut out of the area indicated by yellow circle in (C), highlighting dark lonsdaleite crystals. The diffraction pattern for white area circled is further examined in SI Appendix, Fig. S5 B–F. An example of a TEM image of lonsdaleite from NWA 2705 is shown in SI Appendix, Fig. S5A.