Nanocrystalline hydroxyapatite (HAp) powders were synthesized by a simple method using aloe vera plant extracted solution. To obtain nanocrystalline HAp, the prepared precursor was calcined in air at 400-800 degrees C for 2 h. The phase composition of the calcined samples was studied by X-ray diffraction (XRD) technique. The XRD results confirmed the formation of HAp phase. With increasing calcination temperature, the crystallite of the HAp increased, showing the hexagonal structure of HAp with the lattice parameter, a, in a range of 0.9520-0.9536 nm and c of 0.6739-0.6928 nm. The particle sizes of the powder were obtained to be 43-171 nm. The optical properties of the calcined powders were characterized by Raman and FTIR spectroscopies. The Raman spectra showed a main peak of the phosphate vibration mode (nu(1)(PO(4))) at similar to 963 cm(-1) for all the calcined samples. The peaks of the phosphate carbonate and hydroxyl vibration modes were observed in the FTIR spectra for all the calcined powders. The morphology tends to change from a spherical shape to a rod-like shape with increasing calcination temperature as revealed by TEM. (C) 2009 Elsevier B.V. All rights reserved.