FTIR-RM spectra, XRD patterns, qBSE and stiffness maps and elastic modulus results. (a) Representative Fourier Transform Infrared microspectroscopy in reflectance mode (FTIR-RM) spectra extracted from the maps of Calc1, Calc2, Calc7, Calc8 and Calc10 compared with these of bone, dentin and enamel specimens, and to pressed pellets of physiological apatite and highly crystallized hydroxyapatite. (b) X-ray diffraction (XRD) patterns of powder from Calc7, of the cross sections of Calc7 and Calc8 compared with those obtained from powders of bone, dentin, enamel, physiological apatite and highly crystallized hydroxyapatite. (c) quantitative backscattered electron imaging (qBSE) images and matching stiffness maps obtained from Calc3 and Calc4. The darkest purple represents the highest stiffness and the lightest purple the lowest. (d) Degree of stiffness (elastic modulus) versus the mineral density (MD) measured at the same locations for Calc3 (square) and Calc4 (triangle). Colored data points correspond to data from the dark red, red and pink areas of the qBSE images in c. Hollow symbols correspond to all of the other colored areas in c.