Irradiating experiments on freshwater and seawater cultured pearls using electron accelerator have been done, and lots of colour changed samples have been obtained in the experiments.

The characteristic cathode luminescence is one of the peculiarities to distinguish freshwater cultured pearls, seawater cultured pearls and treated pearls.

Three kinds of pearl natural seawater pearl, farmed seawater pearl, and farmed fresh water pearl have been tested by the confocal micro Raman spectrometer.