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Nacre ( , ), also known as mother-of-pearl, is an organicinorganic
composite material A composite or composite material (also composition material) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a ...
produced by some
mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...
s as an inner
shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses Science Biology * Seashell, a hard outer layer of a marine ani ...
layer. It is also the material of which
pearl A pearl is a hard, glistening object produced within the soft tissue (specifically the mantle (mollusc), mantle) of a living Exoskeleton, shelled mollusk or another animal, such as fossil conulariids. Just like the shell of a mollusk, a pear ...
s are composed. It is strong, resilient, and
iridescent Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear gradually to change colour as the angle of view or the angle of illumination changes. Iridescence is caused by wave interference of light in microstruc ...
. Nacre is found in some of the most ancient lineages of
bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...
s,
gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...
s, and
cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
s. However, the inner layer in the great majority of
mollusc shell The mollusc (or mollusk) shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes. Not all shelled ...
s is porcellaneous, not nacreous, and this usually results in a non-iridescent shine, or more rarely in non-nacreous iridescence such as ''flame structure'' as is found in
conch Conch ( , , ) is a common name of a number of different medium-to-large-sized sea snails. Conch shells typically have a high Spire (mollusc), spire and a noticeable siphonal canal (in other words, the shell comes to a noticeable point on both ...
pearls. The outer layer of cultured pearls and the inside layer of
pearl oyster ''Pinctada'' is a genus of saltwater oysters, marine bivalve mollusks in the family Pteriidae. These pearl oysters have a strong inner shell layer composed of nacre, also known as "mother of pearl". Pearl oysters are not closely related to ...
and
freshwater pearl mussel The freshwater pearl mussel (''Margaritifera margaritifera'') is an endangered species of freshwater mussel, an Aquatic animal, aquatic bivalve mollusc in the family Margaritiferidae. Although the name "freshwater pearl mussel" is often used fo ...
shells are made of nacre. Other mollusc families that have a nacreous inner shell layer include marine gastropods such as the
Haliotidae ''Haliotis'', common name abalone, is the only genus in the family Haliotidae. This genus once contained six subgenera. These subgenera have become alternate representations of ''Haliotis''. The genus consists of small to very large, edible, ...
, the
Trochidae The Trochidae, common name top-snails or top-shells, are a family of various sized sea snails, marine gastropod molluscs in the subclass Vetigastropoda. This family is commonly known as the top-snails because in many species the shell resembles ...
and the
Turbinidae Turbinidae, the turban snails, are a family of small to large marine gastropod molluscs in the superfamily Trochoidea.Bouchet, P. (2014). Turbinidae Rafinesque, 1815. Accessed through: World Register of Marine Species at http://www.marinespecie ...
.


Physical characteristics


Structure and appearance

Nacre is composed of hexagonal platelets, called tablets, of
aragonite Aragonite is a carbonate mineral and one of the three most common naturally occurring crystal forms of calcium carbonate (), the others being calcite and vaterite. It is formed by biological and physical processes, including precipitation fr ...
(a form of
calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...
) 10–20 
μm The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...
wide and 0.5 Î¼m thick arranged in a continuous parallel
lamina Lamina may refer to: People * Saa Emerson Lamina, Sierra Leonean politician * Tamba Lamina, Sierra Leonean politician and diplomat Science and technology * Planar lamina, a two-dimensional planar closed surface with mass and density, in mathem ...
. Depending on the species, the shape of the tablets differs; in '' Pinna'', the tablets are rectangular, with symmetric sectors more or less soluble. Whatever the shape of the tablets, the smallest units they contain are irregular rounded granules. These layers are separated by sheets of organic matrix (interfaces) composed of
elastic Elastic is a word often used to describe or identify certain types of elastomer, Elastic (notion), elastic used in garments or stretch fabric, stretchable fabrics. Elastic may also refer to: Alternative name * Rubber band, ring-shaped band of rub ...
biopolymers Biopolymers are natural polymers produced by the cells of living organisms. Like other polymers, biopolymers consist of monomeric units that are covalently bonded in chains to form larger molecules. There are three main classes of biopolymers, ...
(such as
chitin Chitin (carbon, C8hydrogen, H13oxygen, O5nitrogen, N)n ( ) is a long-chain polymer of N-Acetylglucosamine, ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is the second most abundant polysaccharide in nature (behind only cell ...
, lustrin and
silk Silk is a natural fiber, natural protein fiber, some forms of which can be weaving, woven into textiles. The protein fiber of silk is composed mainly of fibroin and is most commonly produced by certain insect larvae to form cocoon (silk), c ...
-like
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
s). Nacre appears
iridescent Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear gradually to change colour as the angle of view or the angle of illumination changes. Iridescence is caused by wave interference of light in microstruc ...
because the thickness of the aragonite platelets is close to the wavelength of visible
light Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400– ...
. These structures interfere constructively and destructively with different wavelengths of light at different viewing angles, creating structural colours. The crystallographic ''c-''axis points approximately perpendicular to the shell wall, but the direction of the other axes varies between groups. Adjacent tablets have been shown to have dramatically different c-axis orientation, generally randomly oriented within ~20° of vertical. In bivalves and cephalopods, the ''b-''axis points in the direction of shell growth, whereas in the
monoplacophora Shell of Monoplacophora Monoplacophora , meaning "bearing one plate", is a polyphyletic class of molluscs with a cap-like shell, inhabiting deep sea environments. Extant representatives were not recognized as such until 1952; previously they wer ...
it is the ''a''-axis that is inclined this way.


Mechanical properties

This mixture of brittle platelets and the thin layers of elastic biopolymers makes the material strong and resilient, with a
Young's modulus Young's modulus (or the Young modulus) is a mechanical property of solid materials that measures the tensile or compressive stiffness when the force is applied lengthwise. It is the modulus of elasticity for tension or axial compression. Youn ...
of 70 
GPa Grading in education is the application of standardized measurements to evaluate different levels of student achievement in a course. Grades can be expressed as letters (usually A to F), as a range (for example, 1 to 6), percentages, or as num ...
and a yield stress of roughly 70 MPa (when dry). Strength and resilience are also likely to be due to adhesion by the "brickwork" arrangement of the platelets, which inhibits transverse crack propagation. This structure, spanning multiple length sizes, greatly increases its
toughness In materials science and metallurgy, toughness is the ability of a material to absorb energy and plastically deform without fracturing.silicon Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a membe ...
. The mineral–organic interface results in enhanced resilience and strength of the organic interlayers. The interlocking of bricks of nacre has large impact on both the deformation mechanism as well as its toughness.
Tensile Tension is the pulling or stretching force transmitted axially along an object such as a string, rope, chain, rod, truss member, or other object, so as to stretch or pull apart the object. In terms of force, it is the opposite of ''compression ...
, shear, and compression tests, Weibull analysis,
nanoindentation Nanoindentation, also called instrumented indentation testing, is a variety of indentation hardness tests applied to small volumes. Indentation is perhaps the most commonly applied means of testing the mechanical properties of materials. The nanoi ...
, and other techniques have all been used to probe the mechanical properties of nacre. Theoretical and computational methods have also been developed to explain the experimental observations of nacre's mechanical behavior. Nacre is stronger under
compressive In continuum mechanics, stress is a physical quantity that describes Force, forces present during Deformation (physics), deformation. For example, an object being pulled apart, such as a stretched elastic band, is subject to Tension (physics) ...
loads than
tensile Tension is the pulling or stretching force transmitted axially along an object such as a string, rope, chain, rod, truss member, or other object, so as to stretch or pull apart the object. In terms of force, it is the opposite of ''compression ...
ones when the force is applied parallel or perpendicular to the platelets. As an oriented structure, nacre is highly
anisotropic Anisotropy () is the structural property of non-uniformity in different directions, as opposed to isotropy. An anisotropic object or pattern has properties that differ according to direction of measurement. For example, many materials exhibit ver ...
and as such, its mechanical properties are also dependent on the direction. A variety of toughening mechanisms are responsible for nacre's mechanical behavior. The adhesive force needed to separate the proteinaceous and the aragonite phases is high, indicating that there are molecular interactions between the components. In
laminated Simulated flight (using image stack created by μCT scanning) through the length of a knitting needle that consists of laminated wooden layers: the layers can be differentiated by the change of direction of the wood's vessels Shattered windshi ...
structures with hard and soft layers, a model system that can be applied to understand nacre, the
fracture Fracture is the appearance of a crack or complete separation of an object or material into two or more pieces under the action of stress (mechanics), stress. The fracture of a solid usually occurs due to the development of certain displacemen ...
energy and fracture strength are both larger than those values characteristic of the hard material only. Specifically, this structure facilitates crack deflection, since it is easier for the crack to continue into the
viscoelastic In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both Viscosity, viscous and Elasticity (physics), elastic characteristics when undergoing deformation (engineering), deformation. Viscous mate ...
and compliant organic matrix than going straight into another aragonite platelet. This results in the
ductile Ductility refers to the ability of a material to sustain significant plastic deformation before fracture. Plastic deformation is the permanent distortion of a material under applied stress, as opposed to elastic deformation, which is reversi ...
protein phase deforming such that the crack changes directions and avoids the
brittle A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. ...
ceramic phase. Based on experiments done on nacre-like
synthetic materials Synthetic may refer to: Science * Synthetic biology * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic elements, chemical elements that are not naturally found on Earth and therefore have to be created in ...
, it is hypothesized that the compliant matrix needs to have a larger fracture energy than the
elastic energy Elastic energy is the mechanical potential energy stored in the configuration of a material or physical system as it is subjected to elastic deformation by work performed upon it. Elastic energy occurs when objects are impermanently compressed ...
at fracture of the hard phase.
Fiber pull-out Fiber pull-out is one of the failure mechanisms in fiber-reinforced composite materials. Other forms of failure include delamination, intralaminar matrix cracking, longitudinal matrix splitting, fiber/matrix debonding, and fiber fracture. The ca ...
, which occurs in other ceramic
composite material A composite or composite material (also composition material) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a ...
s, contributes to this phenomenon. Unlike in traditional synthetic composites, the aragonite in nacre forms bridges between individual tablets, so the structure is not only held together by the strong
adhesion Adhesion is the tendency of dissimilar particles or interface (matter), surfaces to cling to one another. (Cohesion (chemistry), Cohesion refers to the tendency of similar or identical particles and surfaces to cling to one another.) The ...
of the ceramic phase to the organic one, but also by these connecting
nanoscale Nanotechnology is the manipulation of matter with at least one dimension sized from 1 to 100 nanometers (nm). At this scale, commonly known as the nanoscale, surface area and quantum mechanical effects become important in describing propertie ...
features. As plastic deformation starts, the
mineral bridge In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...
s may break, creating small asperities that roughen the aragonite-protein interface. The additional friction generated by the asperities helps the material withstand shear stresses. In nacre-like composites, the mineral bridges have also been shown to increase the
flexural strength Flexural strength, also known as modulus of rupture, or bend strength, or transverse rupture strength is a material property, defined as the Stress (mechanics), stress in a material just before it Yield (engineering), yields in a flexure test. T ...
of the material because they can transfer stress in the material. Developing synthetic composites that exhibit similar mechanical properties as nacre is of interest to scientists working on developing stronger materials. To achieve these effects, researchers take inspiration from nacre and use synthetic ceramics and polymers to mimic the "
brick-and-mortar Brick and mortar (or B&M) is an organization or business with a physical presence in a building or other structure. The term ''brick-and-mortar business'' is often used to refer to a company that possesses or leases retail shops, factory produc ...
" structure, mineral bridges, and other hierarchical features. When dehydrated, nacre loses much of its strength and acts as a brittle material, like pure aragonite. The hardness of this material is also negatively impacted by dehydration. Water acts as a
plasticizer A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture. Plasticizer ...
for the organic matrix, improving its toughness and reducing its shear modulus. Hydrating the protein layer also decreases its
Young's modulus Young's modulus (or the Young modulus) is a mechanical property of solid materials that measures the tensile or compressive stiffness when the force is applied lengthwise. It is the modulus of elasticity for tension or axial compression. Youn ...
, which is expected to improve the fracture energy and strength of a composite with alternating hard and soft layers. The statistical variation of the platelets has a negative effect on the mechanical performance (stiffness, strength, and energy absorption) because statistical variation precipitates localization of deformation. However, the negative effects of statistical variations can be offset by interfaces with large strain at failure accompanied by strain hardening. On the other hand, the
fracture toughness In materials science, fracture toughness is the critical stress intensity factor of a sharp Fracture, crack where propagation of the crack suddenly becomes rapid and unlimited. It is a material property that quantifies its ability to resist crac ...
of nacre increases with moderate statistical variations which creates tough regions where the crack gets pinned. But, higher statistical variations generates very weak regions which allows the crack to propagate without much resistance causing the fracture toughness to decrease. Studies have shown that this weak structural defects act as dissipative topological defects coupled by an elastic distortion.


Formation

The process of how nacre is formed is not completely clear. It has been observed in ''
Pinna nobilis ''Pinna nobilis'', known by the common names noble pen shell and fan mussel, is a large species of Mediterranean clam, a marine bivalve mollusc in the family Pinnidae, the pen shells.*''Pinna gigas'' Chemnitz It reaches up to of shell length ...
'', where it starts as tiny particles (~50–80 nm) grouping together inside a natural material. These particles line up in a way that resembles fibers, and they continue to multiply. When there are enough particles, they come together to form early stages of nacre. The growth of nacre is regulated by organic substances that determine how and when the nacre crystals start and develop. Each crystal, which can be thought of as a "brick", is thought to rapidly grow to match the full height of the layer of nacre. They continue to grow until they meet the surrounding bricks. This produces the hexagonal close-packing characteristic of nacre. The growth of these bricks can be initiated in various ways such as from randomly scattered elements within the organic layer, well-defined arrangements of proteins, or they may expand from mineral bridges coming from the layer underneath. What sets nacre apart from fibrous aragonite, a similarly formed but brittle mineral, is the speed at which it grows in a certain direction (roughly perpendicular to the shell). This growth is slow in nacre, but fast in fibrous aragonite. A 2021 paper in ''
Nature Physics ''Nature Physics'' is a monthly peer-reviewed scientific journal published by Nature Portfolio. It was first published in October 2005 (volume 1, issue 1). The chief editor is David Abergel. Scope ''Nature Physics'' publishes both pure and appli ...
'' examined nacre from ''
Unio pictorum ''Unio pictorum'', the painter's mussel, is a species of medium-sized freshwater mussel, an Aquatic animal, aquatic bivalve mollusk in the family (biology), family Unionidae, the river mussels. MolluscaBase eds. (2023). MolluscaBase. Unio picto ...
'', noting that in each case the initial layers of nacre laid down by the organism contained spiral defects. Defects that spiralled in opposite directions created distortions in the material that drew them towards each other as the layers built up until they merged and cancelled each other out. Later layers of nacre were found to be uniform and ordered in structure.


Function

Nacre is secreted by the
epithelial Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...
cells Cell most often refers to: * Cell (biology), the functional basic unit of life * Cellphone, a phone connected to a cellular network * Clandestine cell, a penetration-resistant form of a secret or outlawed organization * Electrochemical cell, a d ...
of the mantle tissue of various molluscs. The nacre is continuously deposited onto the inner surface of the shell, the iridescent ''nacreous layer'', commonly known as ''mother-of-pearl''. The layers of nacre smooth the shell surface and help defend the soft tissues against
parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...
s and damaging debris by entombing them in successive layers of nacre, forming either a blister
pearl A pearl is a hard, glistening object produced within the soft tissue (specifically the mantle (mollusc), mantle) of a living Exoskeleton, shelled mollusk or another animal, such as fossil conulariids. Just like the shell of a mollusk, a pear ...
attached to the interior of the shell, or a free pearl within the mantle tissues. The process is called ''encystation'' and it continues as long as the mollusc lives.


In different mollusc groups

The form of nacre varies from group to group. In
bivalves Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consis ...
, the nacre layer is formed of single crystals in a
hexagonal close packing In geometry, close-packing of equal spheres is a dense arrangement of congruent spheres in an infinite, regular arrangement (or lattice). Carl Friedrich Gauss proved that the highest average density – that is, the greatest fraction of space occ ...
. In
gastropods Gastropods (), commonly known as slugs and snails, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and from the land. Ther ...
, crystals are twinned, and in
cephalopods A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
, they are pseudohexagonal monocrystals, which are often twinned.


Commercial sources

The main commercial sources of mother-of-pearl have been the
pearl oyster ''Pinctada'' is a genus of saltwater oysters, marine bivalve mollusks in the family Pteriidae. These pearl oysters have a strong inner shell layer composed of nacre, also known as "mother of pearl". Pearl oysters are not closely related to ...
,
freshwater pearl Cultured freshwater pearls are pearls that are farmed and created using freshwater mussels. These pearls are produced in Japan and the United States on a limited scale, but are now almost exclusively produced in China. The U.S. Federal Trade Com ...
mussels, and to a lesser extent the
abalone Abalone ( or ; via Spanish , from Rumsen language, Rumsen ''aulón'') is a common name for any small to very large marine life, marine gastropod mollusc in the family (biology), family Haliotidae, which once contained six genera but now cont ...
, popular for their sturdiness and beauty in the latter half of the 19th century. Widely used for pearl buttons especially during the 1900s, were the shells of the great green
turban snail Turbinidae, the turban snails, are a family of small to large marine gastropod molluscs in the superfamily Trochoidea.Bouchet, P. (2014). Turbinidae Rafinesque, 1815. Accessed through: World Register of Marine Species at http://www.marinespecie ...
''
Turbo marmoratus ''Turbo marmoratus'', known as the green turban, the marbled turban or great green turban, is a large species of marine gastropod with a thick calcareous operculum in the family Turbinidae, the turban snails.WoRMS (2012). ''Turbo marmoratus'' ...
'' and the large top snail, ''
Tectus niloticus ''Rochia nilotica'', common name the commercial top shell, is a species of sea snail, a marine gastropod mollusk in the family Tegulidae.MolluscaBase eds. (2022). MolluscaBase. Rochia nilotica (Linnaeus, 1767). Accessed through: World Register ...
''. The international trade in mother-of-pearl is governed by the
Convention on International Trade in Endangered Species of Wild Fauna and Flora CITES (shorter acronym for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of inte ...
, an agreement signed by more than 170 countries.


Uses


Decorative


Mother of pearl in ancient china

An ancient art made by mother of pearl in china. This ancient art dates back to the Shang Dynasty. This art is also used on jewelry boxes, decorative items and jewelry. Today this art is one of the chinese cultural heritage.


Architecture

Both black and white nacre are used for
architectural Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and construction, constructi ...
purposes. The natural nacre may be artificially tinted to almost any color. Nacre
tesserae A tessera (plural: tesserae, diminutive ''tessella'') is an individual tile, usually formed in the shape of a square, used in creating a mosaic. It is also known as an abaciscus or abaculus. Historical tesserae In early antiquity, mo ...
may be cut into shapes and
laminated Simulated flight (using image stack created by μCT scanning) through the length of a knitting needle that consists of laminated wooden layers: the layers can be differentiated by the change of direction of the wood's vessels Shattered windshi ...
to a
ceramic A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcela ...
tile Tiles are usually thin, square or rectangular coverings manufactured from hard-wearing material such as ceramic, Rock (geology), stone, metal, baked clay, or even glass. They are generally fixed in place in an array to cover roofs, floors, wal ...
or
marble Marble is a metamorphic rock consisting of carbonate minerals (most commonly calcite (CaCO3) or Dolomite (mineral), dolomite (CaMg(CO3)2) that have recrystallized under the influence of heat and pressure. It has a crystalline texture, and is ty ...
base. The tesserae are hand-placed and closely sandwiched together, creating an irregular mosaic or pattern (such as a weave). The laminated material is typically about thick. The tesserae are then
lacquer Lacquer is a type of hard and usually shiny coating or finish applied to materials such as wood or metal. It is most often made from resin extracted from trees and waxes and has been in use since antiquity. Asian lacquerware, which may be c ...
ed and polished creating a durable and glossy surface. Instead of using a marble or tile base, the nacre tesserae can be glued to
fiberglass Fiberglass (American English) or fibreglass (English in the Commonwealth of Nations, Commonwealth English) is a common type of fibre-reinforced plastic, fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened i ...
. The result is a lightweight material that offers a seamless installation and there is no limit to the sheet size. Nacre sheets may be used on interior floors, exterior and interior walls, countertops, doors and ceilings. Insertion into architectural elements, such as columns or furniture is easily accomplished. Jewelry Mother of pearl is commonly used in jewelry due to its smooth texture and iridescent appearance. It is sourced from the inner layer of mollusk shells, such as oysters and abalones. Mother of pearl is frequently crafted into earrings, pendants, rings, bracelets, and brooches. It can be carved into various shapes or inlaid into metal settings, often combined with gold, silver, or gemstones. The material is valued for its natural luster and the subtle color variations it displays, which can include white, cream, pink, and green.


Musical instruments

Nacre inlay is often used for music
keys Key, Keys, The Key or The Keys may refer to: Common uses * Key (cryptography), a piece of information needed to encode or decode a message * Key (instrument), a component of a musical instrument * Key (lock), a device used to operate a lock * ...
and other decorative motifs on musical instruments. Many
accordion Accordions (from 19th-century German language, German ', from '—"musical chord, concord of sounds") are a family of box-shaped musical instruments of the bellows-driven free reed aerophone type (producing sound as air flows past a Reed (mou ...
and
concertina A concertina is a free-reed musical instrument, like the various accordions and the harmonica. It consists of expanding and contracting bellows, with buttons (or keys) usually on both ends, unlike accordion buttons, which are on the front. The ...
bodies are completely covered in nacre, and some
guitar The guitar is a stringed musical instrument that is usually fretted (with Fretless guitar, some exceptions) and typically has six or Twelve-string guitar, twelve strings. It is usually held flat against the player's body and played by strumming ...
s have fingerboard or headstock inlays made of nacre (or imitation
pearloid Pearloid is a plastic that is intended to resemble mother of pearl. It is commonly used in making musical instruments, especially for pickguards, electric guitar inlays, and accordions. Production Pearloid is produced by swirling together chunks ...
plastic inlays). The
bouzouki The bouzouki (, also ; ; alt. pl. ''bouzoukia'', , from Greek , from Turkish ) is a musical instrument popular in West Asia (Syria, Iraq), Europe and Balkans (Greece, North Macedonia, Bulgaria, Turkey). It is a member of the long-necked lute fam ...
and
baglamas The baglamas ( ), plural '' baglamades'') or baglamadaki (), a long necked bowl-lute, is a plucked string instrument used in Greek music; it is a smaller version of the bouzouki pitched an octave higher (nominally D-A-D), with unison pairs o ...
(Greek plucked string instruments of the
lute A lute ( or ) is any plucked string instrument with a neck (music), neck and a deep round back enclosing a hollow cavity, usually with a sound hole or opening in the body. It may be either fretted or unfretted. More specifically, the term "lu ...
family) typically feature nacre decorations, as does the related Middle Eastern oud (typically around the
sound hole A sound hole is an opening in the body of a stringed musical instrument, usually the upper sound board. Sound holes have different shapes: * Round in flat-top guitars and traditional bowl-back mandolins; * F-holes in instruments from the viol ...
s and on the back of the instrument). Bows of stringed instruments such as the
violin The violin, sometimes referred to as a fiddle, is a wooden chordophone, and is the smallest, and thus highest-pitched instrument (soprano) in regular use in the violin family. Smaller violin-type instruments exist, including the violino picc ...
and
cello The violoncello ( , ), commonly abbreviated as cello ( ), is a middle pitched bowed (sometimes pizzicato, plucked and occasionally col legno, hit) string instrument of the violin family. Its four strings are usually intonation (music), tuned i ...
often have mother-of-pearl inlay at the frog. It is traditionally used on
saxophone The saxophone (often referred to colloquially as the sax) is a type of single-reed woodwind instrument with a conical body, usually made of brass. As with all single-reed instruments, sound is produced when a reed on a mouthpiece vibrates to p ...
keytouches, as well as the valve buttons of
trumpets The trumpet is a brass instrument commonly used in classical and jazz ensembles. The trumpet group ranges from the piccolo trumpet—with the highest register in the brass family—to the bass trumpet, pitched one octave below the standard B o ...
and other brass instruments. The Middle Eastern
goblet drum The goblet drum (also chalice drum, tarabuka, tarabaki, darbuka, darabuka, derbake, debuka, doumbek, dumbec, dumbeg, dumbelek, toumperleki, tumbak, or zerbaghali; / Romanized: ) is a single-head membranophone with a goblet-shaped body. It is ...
(darbuka) is commonly decorated by mother-of-pearl.


Indian mother-of-pearl art

At the end of 19th century, Anukul Munsi was the first accomplished artist who successfully carved the shells of
oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but no ...
s to give a shape of human being which led to the invention of new horizon in Indian contemporary art. For the
British Empire Exhibition The British Empire Exhibition was a colonial exhibition held at Wembley Park, London England from 23 April to 1 November 1924 and from 9 May to 31 October 1925. Background In 1920 the Government of the United Kingdom, British Government decide ...
in 1924, he received a gold medal. His eldest son Annada Munshi is credited with drawing ''Indian Swadesi Movement'' in the form of Indian advertising. Anukul Charan Munshi's third son Manu Munshi was one of the finest mother-of-pearl artists in the middle of 20th century. As the best example of "Charu and Karu art of Bengal," the former
Chief Minister of West Bengal The chief minister of West Bengal (IAST: Paścim Baṅgēr Mukhya Mantrī) is the '' de facto'' head of the executive branch of the Government of West Bengal, the subnational authority of the Indian state of West Bengal. The chief minister is ...
, Dr.
Bidhan Chandra Roy Bidhan Chandra Roy (1 July 1882 – 1 July 1962) was an Indian physician and politician who served as Chief Minister of West Bengal from 1950 until his death in 1962. He played a key role in the founding of several institutions and cities like ...
, sent Manu's artwork, "Gandhiji's Noakhali Abhiyan", to the
United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
. Numerous illustrious figures, such as
Satyajit Ray Satyajit Ray (; 2 May 1921 – 23 April 1992) was an Indian film director, screenwriter, author, lyricist, magazine editor, illustrator, calligraphy, calligrapher, and composer. He is widely considered to be one of the greatest and most influ ...
,
Bidhan Chandra Roy Bidhan Chandra Roy (1 July 1882 – 1 July 1962) was an Indian physician and politician who served as Chief Minister of West Bengal from 1950 until his death in 1962. He played a key role in the founding of several institutions and cities like ...
, Barrister Subodh Chandra Roy, Subho Tagore, Humayun Kabir,
Jehangir Kabir Jehangir Kabir was an Indian Bengali politician and trade union leader. Jehangir Kabir was born on 26 April 1910 in Faridpur, East Bengal (now Bangladesh) to Khabeeruddin Ahmed. Indian educationist Humayun Kabir was Jehangir's elder brother. ...
, as well as his elder brother Annada Munshi, were among the patrons of his works of art. "
Indira Gandhi Indira Priyadarshini Gandhi (Given name, ''née'' Nehru; 19 November 1917 – 31 October 1984) was an Indian politician and stateswoman who served as the Prime Minister of India, prime minister of India from 1966 to 1977 and again from 1980 un ...
" was one of his famous mother of pearl works of art. He is credited with portraying Tagore in various creative stances that were skillfully carved into metallic plates.Anandabazar Patrika. "Munshiana" Publisher:
Anandabazar Patrika ''Anandabazar Patrika'' is an Indian Bengali-language daily newspaper owned by the ABP Group. Its main competitors are ''Bartaman'', '' Ei Samay'', '' Sangbad Pratidin'', " Aajkal", " Jago Bangla", " ganashakti" and " dainik Statesman". Histo ...
His cousin Pratip Munshi was also a famed mother-of-pearl artist.Santanu Ghosh. "Munshianay Chollis Purush" Publisher: Dey's Publishing


Other

Mother-of-pearl
button A button is a fastener that joins two pieces of fabric together by slipping through a loop or by sliding through a buttonhole. In modern clothing and fashion design, buttons are commonly made of plastic but also may be made of metal, wood, or ...
s are used in clothing either for functional or decorative purposes. The
Pearly Kings and Queens Pearly Kings and Queens, known as pearlies, are an organised charitable tradition of working-class culture in London, England. Henry Croft The practice of wearing clothes decorated with mother-of-pearl buttons is first associated with Henry Cro ...
are an elaborate example of this. Mother-of-pearl is sometimes used to make
spoon A spoon (, ) is a utensil consisting of a shallow bowl (also known as a head), oval or round, at the end of a handle. A type of cutlery (sometimes called flatware in the United States), especially as part of a table setting, place setting, it ...
-like utensils for
caviar Caviar or caviare is a food consisting of salt-cured roe of the family Acipenseridae. Caviar is considered a delicacy and is eaten as a garnish or spread. Traditionally, the term caviar refers only to roe from wild sturgeon in the Caspi ...
(i.e. caviar servers) so as to not spoil the taste with metallic spoons. File:Flügelretabel Perlmutt Augsburg um 1520.jpg ,
Altarpiece An altarpiece is a painting or sculpture, including relief, of religious subject matter made for placing at the back of or behind the altar of a Christian church. Though most commonly used for a single work of art such as a painting or sculpture, ...
, , with extensive use of carved nacre File:Powder flask img 2091.jpg , Nacre gunpowder flask, , mostly made of ''
Turbo marmoratus ''Turbo marmoratus'', known as the green turban, the marbled turban or great green turban, is a large species of marine gastropod with a thick calcareous operculum in the family Turbinidae, the turban snails.WoRMS (2012). ''Turbo marmoratus'' ...
'' shell File:Istanbul.Topkapi046.jpg ,
Inlay Inlay covers a range of techniques in sculpture and the decorative arts for inserting pieces of contrasting, often colored materials into depressions in a base object to form Ornament (art), ornament or pictures that normally are flush with the ...
with nacre
tesserae A tessera (plural: tesserae, diminutive ''tessella'') is an individual tile, usually formed in the shape of a square, used in creating a mosaic. It is also known as an abaciscus or abaculus. Historical tesserae In early antiquity, mo ...
,
Topkapı Palace The Topkapı Palace (; ), or the Seraglio, is a large museum and library in the east of the Fatih List of districts of Istanbul, district of Istanbul in Turkey. From the 1460s to the completion of Dolmabahçe Palace in 1856, it served as the ad ...
,
Istanbul Istanbul is the List of largest cities and towns in Turkey, largest city in Turkey, constituting the country's economic, cultural, and historical heart. With Demographics of Istanbul, a population over , it is home to 18% of the Demographics ...
File:Ile Salomon Pendentif MHNT ETH AC SL 23 Roquemaurel.jpg , Engraved nacre pendant,
Solomon Islands Solomon Islands, also known simply as the Solomons,John Prados, ''Islands of Destiny'', Dutton Caliber, 2012, p,20 and passim is an island country consisting of six major islands and over 1000 smaller islands in Melanesia, part of Oceania, t ...
1838


Biomedical use

The biotech company Marine Biomedical, formed by a collaboration between the
University of Western Australia University of Western Australia (UWA) is a public research university in the Australian state of Western Australia. The university's main campus is in Crawley, Western Australia, Crawley, a suburb in the City of Perth local government area. UW ...
Medical School and a Broome pearling business, is developing a product nacre to create "PearlBone", which could be used on patients needing
bone graft Bone grafting is a type of transplantation used to replace missing bone tissue or stimulate the healing of fractures. This surgical procedure is useful for repairing bone fractures that are extremely complex, pose a significant health risk to the ...
ing and
reconstructive surgery Reconstructive surgery is surgery performed to restore normal appearance and function to body parts malformed by a disease or medical condition. Description Reconstructive surgery is a term with training, clinical, and reimbursement implicat ...
. The company is applying for regulatory approval in Australia and several other countries, and is expecting it to be approved for clinical use around 2024–5. It is intended to build a factory in the
Kimberley region The Kimberley is the northernmost of the nine regions of Western Australia. It is bordered on the west by the Indian Ocean, on the north by the Timor Sea, on the south by the Great Sandy Desert, Great Sandy and Tanami Desert, Tanami deserts in t ...
, where pearl shells are plentiful, which would grind the nacre into a product fit for use in biomedical products. Future applications could include
dental filling Dental restoration, dental fillings, or simply fillings are treatments used to restore the function, integrity, and morphology of missing tooth structure resulting from caries or external trauma as well as the replacement of such structure suppor ...
s and
spinal surgery Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the specialty (medicine), medical specialty that focuses on the surgical treatment or rehabilitation of disorders which affect any portion of the nervous system ...
.


Manufactured nacre

In 2012, researchers created calcium-based nacre in the laboratory by mimicking its natural growth process. In 2014, researchers used lasers to create an analogue of nacre by engraving networks of wavy 3D "micro-cracks" in glass. When the slides were subjected to an impact, the micro-cracks absorbed and dispersed the energy, keeping the glass from shattering. Altogether, treated glass was reportedly 200 times tougher than untreated glass.


See also

*
Ammolite Ammolite is an opal-like organic gemstone found primarily along the eastern slopes of the Rocky Mountains of North America. It is commonly unearthed by natural erosion or through the process of various mining practices, within the perimeter of ...
*
Mother-of-pearl carving in Bethlehem Mother-of-pearl carving is a traditional handicraft in Bethlehem, and is said to have been brought to the city by Franciscan friars from Italy in the 15th century. History Bethlehem's position as an important Christian city has for centuries a ...
*
Pearling in Western Australia Pearling in Western Australia includes the harvesting and farming of both pearl A pearl is a hard, glistening object produced within the soft tissue (specifically the mantle (mollusc), mantle) of a living Exoskeleton, shelled mollusk or ...
*
Raden is a Japanese termRaden.
Julyan H. E. Cartwright, Marc-Georg Willinger and Steven M. Stanley (Jan. 6, 2009)
"The Key Role of the Surface Membrane in Why Gastropod Nacre Grows in Towers"
''Proceedings of the National Academy of Sciences of the United States of America'', Vol. 106, No. 1. . * * *


External links


Objects with mother-of-pearl in the Staten Island Historical Society Online Collections Database
{{Authority control Mollusc products Pearls Mollusc anatomy