What is Nacre?

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  • Written By: wiseGEEK Writer
  • Edited By: O. Wallace
  • Last Modified Date: 21 November 2019
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Nacre is crystalline aragonite or calcium carbonate. Shellfish and mollusks excrete it when they are exposed to a parasite or a foreign body introduced into a shell. It is noted for its shine and iridescence, and its coating on shells is called mother of pearl.

In some situations, production of nacre is induced or cultured by introducing a foreign body to a shellfish. This is the case with cultured pearls, where the formation of pearls is accelerated by placing small foreign shell bits in oysters. It essentially “cultures” the production of nacre, resulting in valuable and iridescent pearls. Alternately, fresh pearls or naturally occurring pearls are usually an oyster’s or mussel’s response to parasitic agents. Since the methods for producing this substance are not externally controlled, the quality and size of these pearls can vary.

Nacre also tends to line the inside of mollusk shells. It can even be seen in garden snails, but it is most noticeable and impressive in sea mollusks. From time to time, people can find shells that exhibit either a white or black shine on their interior, often making them appealing to shell collectors.


When not in pearl form, this substance has been used in a variety of decorative forms. Mother of pearl was traditional on shirt buttons, and some brands still use it. It may also be used on the keys or components of musical instruments. The dial on Rolex® and many other high end watches also use mother of pearl.

Nacre may be worked into tiles, designs in the wood of decorative boxes for jewelry, create cufflinks, or be used in jewelry like rings, necklaces, and earrings. It may also be used with porcelain for kitchen and bathroom sinks. The quality of mother of pearl depends upon the thickness of the crystalline forms, and whether or not the nacre has been dyed to produce certain colors.

Though most people associate nacre with ocean-dwelling mollusks, much of what is produced commercially is found among fresh water shellfish like mussels. Though abalone is commonly thought a terrific source for decorative purposes, harvesting of the sea snails can be limited in some areas. Commercial producers often find it easier to use smaller, easier to obtain, and less endangered animals for this purpose.


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Post 7

@OeKc05 – I wish my buttons on my favorite shirt were 100% nacre. I found out after about a year of wearing it that they are much like the fake pearls, though.

They have nacre on the surface, but after many washings, it can start to flake away. This probably isn't the case with some more expensive buttons, but I paid $15 for this shirt, so I'm not entirely surprised.

Post 6

Real pearls are nacre to the core. Fake pearls have nacre as a coating on the top few layers, but they have plastic cores.

Post 5

I love mother-of-pearl jewelry. I have several sets of seashell earrings that are iridescent with nacre.

I've seen seashell jewelry that is coated in gold or silver, but I think that the kind coated with nacre is the most gorgeous. It just seems natural to put mother-of-pearl on a shell, even if it didn't have it to begin with.

Post 4

I have seen nacre as mother-of-pearl on the inside of many shells. The kind that are usually clamped shut can be found on the beach in halves after they have broken apart, and their undersides often are covered in nacre.

I store these shells nacre side up on a shelf in my bedroom. I collect all sorts of beach items, and these are among the prettiest in my collection.

Some souvenir shops add nacre to their decorative trinkets, but I think the most beautiful kind is that which occurs naturally. On a ceramic item, it just looks fake.

Post 3

@anon27267: River beds are also the place where rice pearls are grown. They do this by inserting a piece of oyster shell inside another oyster in the mantle tissue. The shell then creates a blister that eventually forms into a pearl.

For the rice pearl shape, freshwater pearls are chosen specifically because the river oyster is known to make those kinds of pearls. In general, freshwater oysters are known for creating these elongated pearls that aren’t as round as the saltwater varieties.

Post 2

@anon27267: As you know, man-made pearls are made in the oyster farms. These oysters are specifically cultivated for the purpose of growing pearls. They have different characteristics that can include faster growing or rounded pearls.

To create rice pearls, the oysters are chosen specifically because the pearls that they make are elongated. These are also known as drop pearls. It is the exact same process as regular pearls except the fact that the pearls end up in looking like a rice grain.

Post 1

where can we find rice pearls?

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