In this study, we have compared three nanostructuring pathways - heating in a furnace, and hydrothermal processing in water or steam - to determine the capacity for ACP to form monophasic apatite of seven different Ca/P molar ratios (1.67, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8) powders, total carbonate content, inclusion and arrangement in ACP structure to provide an insight into the various nanostructuring possibilities and outcomes. ACP powders were synthesized by precipitation and freeze-drying. The obtained powder and nanostructured samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Nanostructuring was done by heating samples in a furnace and hydrothermally in water and steam. Nanostructured samples were investigated in more detail by FTIR deconvolution. In addition, carbon mass fraction analysis showed the total carbonate ion content.