American Pearl · Pearl Guide

A Brief History of Pearls: Luster of Akoya Pearls

The short answer

Akoya pearls are known for the sharpest, most mirror-like luster of all cultured pearls. They grow in the cool waters off Japan, which slows nacre growth and packs the nacre crystals tightly, so the surface reflects light brilliantly even though Akoya nacre is often only about half a millimeter thick.

Reviewed by American Pearl’s pearl specialists · Updated October 2026

	A brief history of pearls		LUSTER OF AKOYA PEARLS Akoya pearls have the highest luster of all cultured pearls, according to many experts, and it's usually thought to be the result of their nacre coating. What Creates Luster on Akoya Pearls? Akoya pearls are cultured in the cool waters off Japan. The sea there is typically at least 10 to 15 degrees cooler than it is in other locations where cultured saltwater pearls are developed. Because the cooler conditions slow down the nacre excretion process, and because lower temperatures produce nacre with a more compact crystal structure, Akoya pearls have superior reflective and refractive qualities. This typically gives them a higher luster than other pearls have. Although Akoya pearls usually have a thinner nacre coating than other pearls have (it's about a half-millimeter thick in most cases), their luster often shines the brightest. In order to be considered a flawless or nearly flawless pearl, an Akoya must have an extremely high luster with no visible inclusions on its surface.
	How pearls form in oysters
	How pearls are harvested
	How pearls brought to market

	Know your Akoya pearls
	Akoya Pearl Cultivation
	Akoya Pearl Harvesting
	Akoya Pearl Processing
	Akoya Pearl Evaluation

	Quality Factor One: Luster
	Luster of Akoya Pearls
	Quality Factor Two: Surface
	Surface of Akoya Pearls
	Quality Factor Three: Shape
	Shape of Akoya Pearls
	Quality Factor Four: Color
	Color of Akoya Pearls
	Quality Factor Five: Size
	Size of Akoya Pearls

	Know your South Sea pearls
	South Sea Pearl Cultivation
	South Sea Pearl Harvesting
	South Sea Pearl Processing
	South Sea Pearl Quality Evaluation
	Luster of South Sea Pearls
	Surface of South Sea Pearls
	Shape of South Sea Pearls
	Color of South Sea Pearls
	Size of South Sea Pearls

	Know your Tahitian pearls
	Tahitian Pearl Cultivation
	Tahitian Pearl Harvesting
	Tahitian Pearl Processing
	Tahitian Pearl Quality Evaluation
	Luster of Tahitian Pearls
	Surface of Tahitian Pearls
	Shape of Tahitian Pearls
	Color of Tahitian Pearls
	Size of Tahitian Pearls

	Gift Giving Occasions


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Akoya pearl luster: common questions

Why do Akoya pearls have such high luster?

Akoya pearls have such high luster because cooler water slows nacre deposits and produces a compact crystal structure, which reflects and refracts light better. That is why Akoya luster often outshines larger pearls with thicker nacre.

How thick is the nacre on an Akoya pearl?

The nacre on an Akoya pearl is often about half a millimeter thick, thinner than South Sea or Tahitian nacre. Fine Akoya pearls make up for it with very tight, smooth layers.

What does a top-quality Akoya pearl look like?

A top-quality Akoya pearl is flawless or nearly flawless, with extremely high, mirror-like luster and no visible blemishes on its surface.