Gem Corals: classification and Spectroscopic Features

Several gem corals, belonging to the classes Hydrozoa and Anthozoa of the phylum Cnidaria, have been analyzed. These have been previously classified from a zoological point of view. In this paper surface structures, physical data, FTIR- and Raman-spectra of corals with gem potential have been investigated. Spectrophotometric characterisation proved to be a useful tool for determining the main features of the mineral phases (calcite or aragonite) and of the organic content in each sample. Chromophore complexes belonging to the caroteno-proteins of the carotenoid family also could be detected.