Platelet graphite nanofibers have been characterized by scanning electron microscopy, transmission electron microscopy, electron diffraction, X-ray photoemission spectroscopy, and atomic force microscopy. The results show that the graphene sheets are stacked parallel to each other and are perpendicular to the fiber axis; the interlayer spacing is 0.34 nm. A small fraction of carbon atoms are bonded to oxygen. Solid-state nuclear magnetic resonance shows that hydrogenated carbons are under the detection limit (< 5%) and that the nanofibers are dominated by sp(2)-bonded carbons. Mechanical measurements were made on individual nanofibers by nanoindentation.