Presents research on the conditions under which progressive levels of burning may occur to archaeological bone, and how burning damage changes bones' crystal structure and susceptibility to fragmentation or friability. Experiments simulated common patterns of high-temperature bone diagenesis and fragmentation previously documented in Palaeolithic shelter sites. Bones buried up to 6 cm below the coal beds of the experimental fires were carbonized, but calcination occurred only with direct exposure to live coals. Analysis by infrared spectroscopy reveals that marked changes in crystallinity accompany the macroscopic transformations in color and friability of modern, fire-altered bone. Specifically, a monotonic, nonlinear decrease in mean fragment length across six color categories was observed when samples were agitated or trampled, along with a concordant decline in bone identifiability, first with respect to skeletal element and ultimately the recognizability of bone tissue itself. It was found that the molecular signatures of recrystallization in modern burned bones partly overlap with recrystallization caused by weathering after only one to two years of exposure in an arid setting and by partial fossilization of archaeological bones over the long term. While infrared and x-ray diffraction techniques effectively describe heat-induced changes in modern bone mineral and are an important aid for modeling diagenetic processes, these techniques did not reliably identify burning damage to archaeological bones. Cross-referencing readily visible color phases with HCl-insoluble fraction data proves much more effective and economically feasible for the latter purpose.