Treated cultured pearls with a “chocolate” coloration have entered the market from several sources. Gemological, spectroscopic, and chemical analyses were performed on both untreated and treated cultured pearls to provide a better understanding of the “chocolate” treatment process that is used by one company (Ballerina Pearl Co.) and to determine how these products can be identified. It is likely that the organic components in black cultured pearls were bleached to create the brown coloration; no foreign coloring agent was detected. Cultured pearls treated by this method can be identified based on their unusual coloration, characteristic fluorescence, UV-Vis-NIR reflectance and Raman spectra, and trace-element composition.
Treated cultured pearls with a “chocolate” coloration have entered the market from several sources. Gemological, spectroscopic, and chemical analyses were performed on both untreated and treated cultured pearls to provide a better understanding of the “chocolate” treatment process that is used by one company (Ballerina Pearl Co.) and to determine how these products can be identified. It is likely that the organic components in black cultured pearls were bleached to create the brown coloration; no foreign coloring agent was detected. Cultured pearls treated by this method can be identified based on their unusual coloration, characteristic fluorescence, UV-Vis-NIR reflectance and Raman spectra, and trace-element composition.
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