Because it is difficult to classify pearls refering to their physical measured quantities, we propose the following method of classification. The spectral reflectance of pearls relative to a standard metal sphere is determined at eight selected wavelengths by the spherical dome type reflectometer developed by us. From the measured spectral reflectances, two evaluation func-tions are defined as D(580)-D(450) for saturation, and as D' for lightness. Using these evalua-tion functions, we could sort 72 pearls into three different color groups; black, silver and cream, sorted by an experienced pearl-connoisseur.
The excitation and emission processes in the mixture system of organic dyes such as coumarin-1 and spinach chloroplast have been studied. On several samples in vivo and in vitro pumped by a pulsed N2 laser, the energy transfer from the excited organic dye to photosynthetic pigments in chloroplast occured with a high transfer rate. The sensitized fluorescence of chloroplast was observed as a result of this kinetics.