Effects of ${\gamma}$-Ray Irradiation on the Color of Pearl Nucleus

The effect of -ray irradiation on the color of nucleus and cultured pearls was investigated. After () -ray irradiation on the pearl nucleus, its color was altered from brownish to blackish brown or gray depending on irradiation dose. It was clearly found that the all samples are composed of aragonite. ESR spectra were based on the measurement of the paramagnetic species -radicals by the interaction with the -ray irradiation in containing . In this study, we investigated optimal detection method of -ray irradiation to establish destructive or non-destructive test for pearl nucleus.