Judging quality
Genuine nacre feels slightly gritty against a tooth edge and shows fine parallel growth lines under magnification. Plastic imitations are perfectly smooth and warm.
Organic
The nacre lining of pearl oysters and freshwater mussels, cut into plates and cabochons. A soft silvery-white with a slow moving sheen rather than the hard flash of abalone.

Genuine nacre feels slightly gritty against a tooth edge and shows fine parallel growth lines under magnification. Plastic imitations are perfectly smooth and warm.
Avoid acid, perfume and ultrasonics. Wipe with a damp cloth and dry immediately.
Nacre inlay runs through Ottoman furniture, Vietnamese lacquerware and Japanese raden work, all exploiting the same trick of stacked aragonite.
Cultural history, recorded as tradition rather than as medical or scientific claim.
See it in person
Both rooms are open six days a week, and there is always someone happy to pull pieces out of the case so you can compare them under the light.