The patterns in X-ray diffraction (XRD) spectroscopy provide useful clue at 29.4˚ to discriminate two types of Akoya cultured pearl which occurs difference of surface luster. Using the optical microscope, we could be confirmed that the nareous layer of each sample consist of different crystal form. In Fourier Transform Infrared (FT-IR) Spectroscopy analysis, the nareous layer of Akoya cultured pearls with poor luster shows some peaks at 712, 699, 1435, 1444 cm-1 region and these peaks depend on the Calcite. But the nareous layer of pearls with excellent luster could not observed those peaks related with Calcite, we could observed Aragonite band at 699, 1085 cm-1 region. Though this result, we know that the nareous layer of Akoya cultured pearls with excellent luster is mainly composed by Aragonite. Raman bands are also clearly demonstrated to occur difference of band intensity by difference of Aragonite content. In the Scanning Electron Microscope (SEM) analysis, we found that the Akoya cultured pearl luster and surface condition is associated with internal structure.
