Some cortical bone specimens from the femurs of adult cows and sea coral of Porites species were studied by using Fourier Transform Infrared Spectroscopy, FTIR. Carbonate were shown to be present by indication of C-O stretch found between 1510-1410 cm -1 in both cortical bone and Porites. Based on the comparison of the relative intensity of CO3 2- bands with respect to the PO4 3- bands, peak intensity of Porites was found to be higher than peak intensity of cortical bone at carbonate band. This explains that Porites skeleton is made up of CaCO3 while bone consists of a mineral, hydroxyapatite Ca5(PO4)3OH with the present of carbonate ions, typically from 3 to 7 wt%.