“…The bulk shell biomineral phase is observed in all shell types and consists of calcite (CaCO 3 ), as revealed by the characteristic Raman bands at 155, 281, 713, and 1086 cm −1 , corresponding to its T, L, ν 4 , and ν 1 (CO 3 2− ) vibrational modes. 18 In crustaceans, the biomineral phase is reinforced by a network of chitin and protein fibers, 10,19,20 which is evidenced in Raman spectra by specific bands, such as that at 953 cm −1 and a series of weaker bands in the 1200−1450 cm −1 range 21,22 and the amide I band of proteins at 1655 cm −1 and in the high wavenumber range at 2878 and 2932 cm −1 , respectively 23 (Figure 3, blue spectra). The differences in intensities of these bands reflect the natural variation of shell composition between the crustacean species.…”