Orient is described as rainbow hues glistening across the surface and beneath the surface of the pearl. This is caused by the overlapping layers of nacre that is apparent on the pearl. The nacre is actually overlapping crystal plates with irregular edges. The light shining on the strong orient pearl strikes the nacre plates, and the light interacts differently with each layer of nacre. This then causes interference in the light, and the component colors are what results. This is called Orient.
Having a strong orient is very rare in a pearl. Approximately 0.1% of pearls have this orient color in them.
Round, clean pearls with strong orient are usually the very best 0.1% of a pearl harvest. They are usually so good that they are not drilled, but sent to pearl auctions and shows where they are bought as single pearls. Only recently have very few processors been able to create pearl strands out of these beautiful pearls. If one can obtain a piece of pearl jewelry of this quality, it would be a prized possession.