After auction, hama-age pearls are sent to processing factories throughout Japan. There the pearls undergo sorting, treatment, drilling, matching, and final preparation before entering the international jewelry market.

The first stage of processing involves additional sorting by size, shape, luster, color, surface quality, and nacre characteristics. Pearls exhibiting exceptional luster and matching may be separated for higher-end classification, including hanadama-level material.

Maeshori and Post-Harvest Treatment

Most akoya pearls undergo some form of post-harvest treatment. The degree of processing varies depending on the quality and natural appearance of the harvested pearls.

One of the most important early steps is maeshori, or pre-treatment. This process stabilizes the pearls and prepares them for further processing. Exact methods vary among processors and are often closely guarded within the industry. Some exceptionally fine pearls may receive only minimal treatment after maeshori, while others undergo additional whitening and overtone adjustment.

Bleaching is commonly performed using hydrogen peroxide to create a more even white bodycolor. After bleaching, many akoya pearls undergo pinking, a treatment used to enhance the subtle rosé overtone traditionally associated with Japanese akoya pearls.

Not all akoya pearls are processed to the same appearance. Some producers intentionally preserve natural silver, cream, blue, or silver-blue bodycolors rather than processing the pearls toward a bright white finish. As a result, two strands with similar appearance may have undergone very different treatment histories.

Drilling, Matching, and Automation

Pearls are then drilled and polished before being matched into strands, pairs, or jewelry layouts. Matching is one of the most labor-intensive parts of the process. Technicians sort through large quantities of pearls searching for similarities in luster, color, shape, overtone, nacre quality, and surface appearance.

Although many aspects of processing remain highly specialized, automation has become increasingly common in modern factories. Machines are now used for portions of sorting, drilling, and temporary strand assembly, though final grading and matching still rely heavily on trained human judgment.

Processing Standards and Disclosure

Processing standards and disclosure practices continue to evolve throughout the pearl industry. In recent years, organizations such as CIBJO have increasingly emphasized clearer disclosure of pearl treatments, particularly bleaching and related processing methods.

Understanding processing is therefore an important part of evaluating modern akoya pearls, since treatment can significantly influence bodycolor, overtone, luster, and overall appearance.