Pigments from red coral (Corallium rubrum) and African snail (Helixia aspersa) shell were studied non-invasively using Raman spectroscopy with 1064-nm laser beam. The two observed bands because of organic pigments confined in biomineralized CaCO 3 matrix at about 1500 and 1100 cm À1 were assigned to ν(C¼C) and ν(C-C), respectively. Both signals originate from polyene(s) of largely unknown structure, containing several conjugated C¼C bonds. The small peak at 1016 cm À1 in the Raman spectrum of coral pigment was assigned to in-plane -CH 3 rocking or structural deformation of polyene chain because of spatial confinement in the mineral matrix. The organic pigments in red coral and snail shell were present in inorganic matrix containing aragonite (shell) and calcite (coral). In addition, using Raman spectroscopy, it was observed that aragonite was replaced by calcite as result of healing damaged parts of snail shell. This is an important finding which indicates a great potential of nondestructive Raman spectroscopy instead of X-ray technique, as a diagnostic tool in environmental studies. To support analysis of the observed Raman spectra detailed calculations using density functional theory (DFT with B3LYP and BLYP density functionals) on structure and vibrations of model all-trans polyenes were undertaken. DFT calculated C¼C and C-C stretching frequencies for all-trans polyenes containing from 2 to 14 C¼C units were compared with the observed ν(C¼C) and ν(C-C) band positions of the studied coral and shell. Individual correction factors were used to better match theoretical wavenumbers with observed band positions in red coral and African snail. It was concluded that all-trans polyene pigments of red coral and dark parts of African snail shell contain 11-12 and 14 C¼C double bond units, respectively. However, Raman spectroscopy cannot produce any clear information on the presence and nature of the end-chain substituents in the studied pigments.