Question:  Why are Black Akoya pearls really dark blue? Thank you!  Linda R.Wisconsin  Answer:  Hi Linda, The majority of color treatments for enhanced Akoya pearls are done in the processing plants in Japan and Hong Kong, but in truth very little is known about the processes as the details are kept under lock and key by the processing technicians-turned-artists.   The production of modern dyes did not come into being until 1856, when the first synthesized organic dye was invented by Sir William Perkin. During an experiment to help his mentor create artificial quinine (a compound required for the treatment of malaria) he combined oxidized aniline and potassium dichromate.  Aniline is a chemical compound resulting from the distillation of the Indigo-yielding plant Indigofera anil, the name anil being derived from the Sanskrit nila: dark blue. Japanese pearl processors began sending their first cultured pearls for color enhancement to Paris in the 1920’s where the largest dye houses were located at the time. Although the method of dyeing was well known, the actual coloring agents employed remained a secret for decades.  Aniline dyes come in thousands of colors, but the most popular and traditional pigments for Akoya pearls are blue, purple, green and brown. The resulting pearl color is neither ‘black’ nor a true blue, green or purple, but rather a blackish-blue or blackish-green that is extremely distinctive.  The pearls are submerged in the dye, which is heated, until the pearls attain the right saturation levels. The porous surface of the pearl allows the dye to seep through the surface and penetrate the underlying crystalline and organic layers. There, the pigment circulates and then concentrates in the concentric conchiolin layers of the pearl. The darker conchiolin layers are able to absorb the dye easily over an immersion period of several weeks that ensures the correct color levels are attained and evenly distributed over the surface of the pearl.

Tags: Black Akoya, black pearls, Pearl Dyes, Pearl Treatments

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