Cultured pearl

In response, the mantle tissue of the mollusk secretes nacre into the pearl sac, a cyst that forms during the healing process.

The most popular and effective method for creating cultured pearls utilizes the shells of freshwater river mussels harvested in the Midwestern U.S., from Canada to the Gulf of Mexico.

Shells with the common names "Washboard", "Maple Leaf", "Ebony", "Pimpleback", and "Three Ridge" are popular for use in pearl culture due to their compatibility with the host animal and the nacre they are to be covered by.

The edges and corners are ground down until they are a roughly spherical and then milled to become perfectly round, and brought to a highly polished finish.

This perliculture process was first developed by British biologist William Saville-Kent, who passed the information along to Tatsuhei Mise and Tokichi Nishikawa from Japan.

As they grow in the mantle, where on each wing up to 25 grafts can be implanted, these pearls are much more frequent and saturate the market completely.

large, near perfectly round, bead-nucleated pearls up to 15 mm in diameter with metallic luster have been produced.

An experimental process using a radio-frequency identification nucleus allows the provenance of cultured pearls to be tracked.

After the patent was granted in 1916, the technology was immediately commercially applied to akoya pearl oysters in Japan in 1916.

Mitsubishi's Baron Iwasaki immediately applied the technology to the South Sea pearl oyster in 1917 in the Philippines, and later in Buton and Palau.