Technology and Identification of Golden Dyed Pearls

The golden dyed experiments of freshwater cultured pearl samples are done by chrysophenine G dyeing. The relative perfect conditions for dyeing are acquired by using orthogonal experiments for analysing four influence factors of dyeing. The results of expanding treatment and colour fixation treatment show that the concentration of expanding solvent including benzenne and ammonia decreased by distill water can reduce the damage to the nacreous layers of pearls, especially for loose layers of pearl samples. The bluestone liquor is more fit for colour fixation treatment.The identification characteristics of golden dyed pearls are that the dyestuff is concentrated into the blemish, crack and drilled holes on the surface of the samples.The yellowish green fluorescence from the samples could be observed under ultraviolet light, and the Raman spectra show the strong fluorescence background.