akoya engagement ring - pearl treatmentsakoya engagement ring - pearl treatments

Pearl Treatments and Enhancements


Did you know that routine pearl treatments are the most common enhancements in the gem trade? Learn more about these procedures and how they impact prices.

3 Minute Read

HomeLearning CenterGemologyGemstone TreatmentsPearl Treatments and Enhancements

Routine Pearl Treatments

Large factories in Japan and China process pearls in bulk. Since these are the major producers of pearls, this results in uniform appearance and excellent matching for most pearl strands. After pre-treatment washing, most pearls undergo bleaching, dyeing, and a light polishing, and some types also receive luster enhancement. While many people view dyeing negatively, there’s little to no stigma associated with these routine pearl treatments.

Washing

Once out of the shell, pearls are tumbled in a mildly abrasive saltwater solution that removes stuck organic matter.

After this step, experts grade the pearls, which determines their subsequent level of treatment. Only top-quality pearls receive no further treatment. (For Akoya pearls, for example, these are Hanadama-quality). Sellers may also advertise other cultured pearl types as untreated.

Maeshori Luster Enhancement

Most pearls undergo maeshori (Japanese for “before treatment”), a secretive luster enhancement process. This involves a hot-and-cold treatment, and the exact steps vary between factories. In fact, some factories even combine the heating process with bleaching chemicals.

Ultimately, maeshori tightens nacre layers, which drives water out of the pearl. Many liken this treatment to a “facelift” for the pearl.

While this results in a higher…


Addison Rice

A geologist, environmental engineer and Caltech graduate, Addison’s interest in the mesmerizing and beautiful results of earth’s geological processes began in her elementary school’s environmental club. When she isn’t writing about gems and minerals, Addison spends winters studying ancient climates in Iceland and summers hiking the Colorado Rockies.

Never Stop Learning

When you join the IGS community, you get trusted diamond & gemstone information when you need it.

Become a Member

Get Gemology Insights

Get started with the International Gem Society’s free guide to gemstone identification. Join our weekly newsletter & get a free copy of the Gem ID Checklist!