The Akoya pearl

The cold, and the slowness that follows from it.

Akoya, in Japanese, means cultured pearl. It is born in the cold bays of the Japanese archipelago, inside Pinctada martensii, a small oyster highly sensitive to water temperature: below thirteen degrees it slows the deposition of nacre, and between twenty-three and thirty degrees it performs it best.

From that slow growth come the qualities that have been sought in an Akoya for a century: the sharpness of the lustre, the liveliness of the orient and the regularity of the shape. Lustre is the light the surface sends back; orient is the iridescence that surfaces from beneath, produced by the exceedingly thin layers of aragonite. They are also the qualities that make it the pearl of the strand, where every gem must resemble the one beside it.

Diameters range from two to ten millimetres, and the most common sizes lie between seven and eight. The native colours are white and cream, with pink or green overtones.

In the maison's Akoya pearls. Native colour · integrity and compactness of the nacre · every gem admitted only when lustre, orient, shape and structural integrity correspond to the MIMÍ master pearls.

The seven factors by which a pearl is read, and the difference between lustre and orient: How a pearl is judged. What determines the value of a gem: What determines the price of a pearl.

Text by the MIMÍ Milano gemmologists · updated 9 September 2026