The transmission electron microscopy will be used to elucidate the atomic-scale damage produced in naturally-occurring apatite an zircon by induced fission of substituent U-235. Objectives of the research are to characterize the general structure of unannealed latent fission tracks in apatite, to obtain lattice-fringe images within and adjacent to fission tracks in apatite, and to characterize the general structure of unannealed latent tracks in zircon. Crystals to be examined in this study are zircon and Durango apatite (a near end-member fluorapatite). Observations on the apatite will require a cold-stage maintained at liquid nitrogen temperatures in order to minimize beam damage to the crystals and prevent thermal annealing of the fission tracks. Observations on both minerals will be made under varying experimental conditions (e.g., different electron microscopes using various detector systems and collection methods, and different voltages, modes of imaging, crystal orientations. etc.).