The derivation of the term NACRE is uncertain.

Nacre or the Mother of the Pearl: is the inner iridescent layer of molluscan shells (shell in which the precious pearl is formed). Nacre is composed of brittle calcium carbonate crystals known as aragonite with conchiolin which acts like a glue or cement. Though nacre has a hardness of only 2.5 to 4.5 on the Mohs scale, due to its lack of cleavage and irregular brick-and-mortar-like crystal structure, it is a tough and durable material.

Mother-of-Pearl and Pearl, are the same in chemical composition. And Depending on the environment in which the mollusks grow, they can come in white, gray, silver, yellow, blue-green, bronze, pink, red, brown, black or banded.

Nacre is translucent to opaque and has a pearl-like luster and iridescence.

“Orient” is the trade name for the iridescent Nacre.

The Black Mother of Pearl comes with a weak red to reddish fluorescence; whereas the River Mother of Pearl has a strong pale-green fluorescence.

Mollusks that produces pearls are more common than pearls and are found all over the world. They are more common because not all Mollusks will produce a pearl.

Nacre has been used for centuries as jewelry and ornamental pieces.

In the Sumerian Tombs of Ur as well as ancient Egyptian tombs, mother-of-pearl decorated inlays and mosaics were found.

The ancient Egyptians often used it to embellish silver pieces. Plaques with inlays dated to 2500 BC were also discovered.

Native Americans used mother-of-pearl to create beads and jewelry.

Since the Shang Dynasty, Chinese has been making exquisite and detailed lacquer furniture with mother-of-pearl inlays.

In Muslim countries, nacre was used to create beautiful religious art. Aztecs and other Mesoamericans also used mother-of-pearls as inlays for their religious artifacts.

Nacre was very popular during the Victorian Era in Europe. It was used extensively to make inlays to decorate almost every household item including knives, jewelry boxes, buttons and screens.

The United States produced and made nacre buttons in great quantities since a century ago. These are classic favorites by high-quality shirt makers.

Nacre is also used as decorative motifs in musical instruments and for the keys of piano, fingerboard of guitars, accordion and concertina bodies.

Powdered nacre is popularly used in cosmetics. This natural marine ingredient has been used for its healing and iridescent properties for over 2,000 years. Luxurious creams and natural soap are made from nacre. It also has growing applications in dental and bone restoration.

Nacre shells usually come in large sizes and are flat, thick and roundish.

Abalone produces the most beautiful nacre which comes in beautiful purple, blue and green colors. Abalone nacre is also known as the "sea opal" because of its strong opalescence sheen.

Certain mollusks species produce porcelain-like or a porcelaneous luster and a flame-like iridescent pattern. These Nacre include the Conch Shell and the Melo Melo Shells.

Mother-of-pearl are often cut en cabochon and used as gem pieces. Nacre is often treated to produce a uniform white color, to even out the pearl color, to change the color pigments or to enhance its luster.

A mother-of-pearl gem will usually be assembled as a doublet or triplet. This means that one or more materials will be fused in layers. This is to make the gem stronger. In a doublet, the main gem nacre will be affixed to a stronger base of a darker material. This darker mineral adds thickness and strength to the nacre. It also creates a nice contrast to bring out the fiery iridescence display of nacre.

In a triplet setting, the assembled gem receives a protective cap, like a colorless quartz, which further protects the nacre from scratches and fading.

Generally a gemstone is a mineral of non-organic material whereas a gem refers to a small group of organic material such as coral, amber, jet, ivory, ammolite and pearl.

Nacre and pearls come from the same organism of bivalve mollusks or marine gastropods.

The mother of pearl represents the Moon or the Goddess of the Dark Night who is Leto, the mother of Apollo, the Sun god and Diana (or Artemis), the Moon goddess. One of the epithets of Mother Leto was Chryselakatos (of the Golden Spindle). Mother-of-pearl is therefore a symbol for the moon and was used to represent the mystery of the deep ocean.

She is the mother who carries within herself these two awesome powers of the Sun and the Moon. Nacre being the mother-of-pearl, is thus associated with the Mother-Goddess and her life-giving forces.

Traditionally, across civilisations, mother-of-pearl is seen as a giver of prosperity and health. It was used to treat heart palpitations, dizziness and increased blood pressure. Powered nacre is also ingested as a cure for eye ailment.

The pearly luster and iridescence of mother-of-pearl can be dulled by perspiration. It is recommended to clean it with a soft cloth and a mild soap after being worn. Make sure to rid of all soapy residue.

Mother-of-pearl can be found all over the world in both saltwater and freshwater. Important nacre sources include Australia, Japan, Central America, the Persian Gulf, the Gulf of Manaar (between India and Sri Lanka), Madagascar, Burma (Myanmar), the Philippines, the South Pacific Islands, South America, China, French Polynesia, Europe, North America and Southeast Asia.