the inner surface of the shell

The iridescent inside of a mollusk shell, which is used as an ornament. Not to be confused with pearl.

Nacre is the substance a pearl oyster produces layer upon layer that defines a pearl. A trained eye can superficially see a thick or thinness to nacre. However, nacre depth can only be determine by x-ray, hence the need for a proper pearl appraisal. Thick nacre is desirable and may determine the quality of the pearl. By x-ray one can see the journey of the nacre's formation by the oyster. These formations are similar to finger prints and are the tell tale signs of origin, quality and worth of a pearl. Nacre in pearl trading can also refer to the pearls surface where the trader is viewing the nacre for luster, depth and over all character – all contribute to the perceived pearl quality. All will become a perception of worth by the buyer (trader and other consumer) and will assist in pricing. In formal pearl grading systems, nacre quality will determine the grade of the pearl and will contribute to its price value.

na'cre (Fr nacre=mothe-of-pearl) The pearly or iridescent substance which lines the interior of some mollusk shells.

the inner-most layer of shell that often has a pearl-like appearance

The calcium carbonate-based substance secreted by a pearl in response to an irritant, such as a piece of shell (cultured pearl) or parasite (most natural pearls).

the iridescent internal layer of a mollusk shell

The usually whitish crystalline substance which the mollusc secretes around a foreign "intruder" and which forms what we know as the pearl. Layers build up over time.

Innermost lustrous layer of mollusc shell, secreted by mantle epithelium. Adj., nacreous.

Soft coating of calcium carbonate that pearl-producing mollusks produced around foreign objects introduced into their bodies.

The crystalline substance secreted by a mollusk to form a pearl. The exterior layer of a cultured pearl.

the interior layer of the shell, usually white, pink, salmon, or purple and iridescent

The iridescent substance containing aragonite and calcite crystals. This is an important outside layering material and a constituent of a pearl and cultured pearls. The thicker the nacre the longer the pearl has been allowed to grow. This results in longer durability.

The crystalline substance secreted by a mollusk that coats the irritant, eventually producing a pearl.

(pronounced “nayker”) - Also known as mother-of-pearl, it is a combination of calcium carbonate and organic substances secreted by certain species of mollusk. It is used both as a means to smooth the animal's shell and as a defense against irritation caused by foreign objects. The nacre is the essential material forming the outer layers of pearls, and a pearl's value is partly determined by the thickness of the nacre.

the mother-of-pearl layer lining the internal surface of musselâ€(tm)s shell; its color is useful in species identification

The mother of pearly secretion of an oyster which forms a pearl.

is the pearly substance secreted by the mantle of certain molluscs to form a pearl. Nacre also creates the beautiful mother-of-pearl coating found on the inside of pearl shells and several other varieties of shellfish.

The substance secreted by the oyster or other mollusk that surrounds the darker conchiolin and subsequently forms the outer layers of the pearl.

The substance that makes a pearl a pearl. This is the natural substance secreted by the mollusk to make pearl and mother-of-pearl. Nacre is layered, consisting of the mineral aragonite (a form of calcium carbonate) and conchiolin. The thickness of nacre is one of the quality factors of the pearl.

Nacre is a usually whitish crystalline substance which oysters, mussels, snails, and other mollusks secrete around a foreign object (like a tiny stone) that has made its way into their shell. As layers of nacre coat the intruder, a pearl is formed over a period of many years.

See mother-of-pearl.

A shiny, iridescent substance secreted by a mollusk in response to a foreign substance such as a grain of sand or an inserted bead. Layers of nacre form a pearl.

The mother-of-pearl secretions of the mollusk; pearl essence.

Nacre is a silky substance secreted over a forming pearl. Layer after layer of nacre build up to form what we call a pearl. When light touches the pearl, it travels through all the layers of nacre, and each tiny crystal reflects the light like miniature prisms. The end result? A lustrous, breathtaking pearl.

(nay-ker) A calcium carbonate-based crystalline substance secreted by mollusks to form mother-of-pearl, pearls, and cultured pearls. Nacre secretion by a mollusk is usually a defense mechanism triggered by the intrusion of a foreign object into the body of an oyster. Thicker nacre translates into a more durable pearl. Natural pearls are all nacre, whereas most cultured pearls have a bead nucleus in the center. The chemical composition of Nacre is: 90% of calcium carbonate crystals (aragonite); 5% of organic protein (conchiolin) that binds the aragonite crystals together; 2% of water; Sodium, magnesium, strontium.

Nacre is the calcium carbonate substance secreted by a mollusk as a defensive measure against a foreign irritant in its body.

A shiny, iridescent substance made from the lining of mollusk shells or fish scales.

The shiny iridescent substance secreted by a mollusk as a response to an irritant, like a piece of sand. Over time layers of nacre build up to become a pearl.

Nacre, also known as mother of pearl, is a naturally-occurring organic-inorganic composite.