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Nacre ( , ), also known as mother of pearl, is an organicinorganic
composite material A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...
produced by some
mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000  extant species of molluscs are recognized. The number of fossil species is est ...
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 ** Thin-shell structure Science Biology * Seashell, a hard o ...
layer; it is also the material of which
pearl A pearl is a hard, glistening object produced within the soft tissue (specifically the mantle) of a living shelled mollusk or another animal, such as fossil conulariids. Just like the shell of a mollusk, a pearl is composed of calcium carb ...
s are composed. It is strong, resilient, and
iridescent Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, butterfl ...
. Nacre is found in some of the most ancient lineages of
bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of marine and freshwater Mollusca, molluscs that have laterally compressed bodies enclosed by a shell consisting of two hing ...
s,
gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...
s, and
cephalopod A cephalopod is any member of the molluscan class Cephalopoda ( Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
s. However, the inner layer in the great majority of
mollusc shell The mollusc (or molluskOften spelled mollusk shell in the USA; the spelling "mollusc" are preferred by ) shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, wh ...
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 and a noticeable siphonal canal (in other words, the shell comes to a noticeable point at both ends). In North Am ...
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 e ...
and
freshwater pearl mussel The freshwater pearl mussel (''Margaritifera margaritifera'') is an endangered species of freshwater mussel, an aquatic bivalve mollusc in the family Margaritiferidae. Although the name "freshwater pearl mussel" is often used for this species, ...
shells are made of nacre. Other mollusc families that have a nacreous inner shell layer include marine gastropods such as the Haliotidae, the Trochidae 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.marinespecies ...
.


Physical characteristics


Structure and appearance

Nacre is composed of hexagonal platelets of
aragonite Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including pre ...
(a form of calcium carbonate) 10–20 
µm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer ( American spelling), also commonly known as a micron, is a unit of length in the International System of Uni ...
wide and 0.5 µm thick arranged in a continuous parallel
lamina Lamina may refer to: Science and technology * Planar lamina, a two-dimensional planar closed surface with mass and density, in mathematics * Laminar flow, (or streamline flow) occurs when a fluid flows in parallel layers, with no disruption betwee ...
. 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 used in garments or stretchable fabrics. Elastic may also refer to: Alternative name * Rubber band, ring-shaped band of rubber used to hold objects togethe ...
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, c ...
(such as
chitin Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...
, lustrin and
silk Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from th ...
-like
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
s). 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 E, the Young modulus, or the modulus of elasticity in tension or compression (i.e., negative tension), is a mechanical property that measures the tensile or compressive stiffness of a solid material when the force is applied ...
of 70  GPa 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 with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic ...
. 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 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. Nacre appears
iridescent Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, butterfl ...
because the thickness of the aragonite platelets is close to the wavelength of visible
light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 t ...
. 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 Monoplacophora , meaning "bearing one plate", is a polyphyletic superclass of molluscs with a cap-like shell inhabiting deep sea environments . Extant representatives were not recognized as such until 1952; previously they were known only from ...
it is the ''a''-axis that is this way inclined. The interlocking of bricks of nacre has large impact on both the deformation mechanism as well as its toughness. In addition, the mineral–organic interface results in enhanced resilience and strength of the organic interlayers.


Formation

Nacre formation is not fully understood. The initial onset assembly, as observed in '' Pinna nobilis'', is driven by the aggregation of nanoparticles (~50–80 nm) within an organic matrix that arrange in fibre-like polycrystalline configurations. The particle number increases successively and, when critical packing is reached, they merge into early-nacre platelets. Nacre growth is mediated by organics, controlling the onset, duration and form of crystal growth. Individual aragonite "bricks" are believed to quickly grow to the full height of the nacreous layer, and expand until they abut adjacent bricks. This produces the hexagonal close-packing characteristic of nacre. Bricks may nucleate on randomly dispersed elements within the organic layer, well-defined arrangements of proteins, or may grow
epitaxially Epitaxy refers to a type of crystal growth or material deposition in which new crystalline layers are formed with one or more well-defined orientations with respect to the crystalline seed layer. The deposited crystalline film is called an epit ...
from mineral bridges extending from the underlying tablet. Nacre differs from fibrous aragonite – a brittle mineral of the same form – in that the growth in the c-axis (i.e., approximately perpendicular to the shell, in nacre) is slow in nacre, and 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 Andrea Taroni, who is a full-time professional editor employed by this ...
'' examined nacre from various
sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throu ...
s and
mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000  extant species of molluscs are recognized. The number of fossil species is est ...
s, 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 one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellu ...
cells Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...
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 close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson h ...
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) of a living shelled mollusk or another animal, such as fossil conulariids. Just like the shell of a mollusk, a pearl is composed of calcium carb ...
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 (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
, 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 occu ...
. In
gastropods The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. The ...
, crystals are twinned, and in
cephalopods A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, a ...
, 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 e ...
,
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 ...
mussels, and to a lesser extent the
abalone Abalone ( or ; via Spanish , from Rumsen ''aulón'') is a common name for any of a group of small to very large marine gastropod molluscs in the family Haliotidae. Other common names are ear shells, sea ears, and, rarely, muttonfish or mutto ...
, 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 ''
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''. 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 name 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 intern ...
, an agreement signed by more than 170 countries.


Uses


Decorative


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 constructing buildings o ...
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 The oldest known tessera ...
may be cut into shapes and
laminated Lamination is the technique/process of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance, or other properties from the use of the differing materia ...
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, porcelain, ...
tile Tiles are usually thin, square or rectangular coverings manufactured from hard-wearing material such as ceramic, stone, metal, baked clay, or even glass. They are generally fixed in place in an array to cover roofs, floors, walls, edges, or ...
or
marble Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term ''marble'' refers to metamorphose ...
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 (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cl ...
. 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.


Musical instruments

Nacre inlay is often used for music
keys Key or The Key may refer to: Common meanings * Key (cryptography), a piece of information that controls the operation of a cryptography algorithm * Key (lock), device used to control access to places or facilities restricted by a lock * Key (m ...
and other decorative motifs on musical instruments. Many
accordion Accordions (from 19th-century German ''Akkordeon'', from ''Akkord''—"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 ree ...
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 fretted musical instrument that typically has six strings. It is usually held flat against the player's body and played by strumming or plucking the strings with the dominant hand, while simultaneously pressing selected string ...
s have fingerboard or headstock inlays made of nacre (or imitation pearliod plastic inlays). The
bouzouki The bouzouki (, also ; el, μπουζούκι ; alt. pl. ''bouzoukia'', from Greek ), also spelled buzuki or buzuci, is a musical instrument popular in Greece. It is a member of the long-necked lute family, with a round body with a flat top and ...
and
baglamas The baglamas ( el, μπαγλαμάς) (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 ...
(Greek plucked string instruments of the
lute A lute ( or ) is any plucked string instrument with a 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 "lute" can ref ...
family) typically feature nacre decorations, as does the related Middle Eastern
oud , image=File:oud2.jpg , image_capt=Syrian oud made by Abdo Nahat in 1921 , background= , classification= * String instruments *Necked bowl lutes , hornbostel_sachs=321.321-6 , hornbostel_sachs_desc=Composite chordophone sounded with a plectrum , ...
(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 vio ...
s and on the back of the instrument). Bows of stringed instruments such as the
violin The violin, sometimes known as a '' fiddle'', is a wooden chordophone ( string instrument) in the violin family. Most violins have a hollow wooden body. It is the smallest and thus highest-pitched instrument ( soprano) in the family in regu ...
and
cello The cello ( ; plural ''celli'' or ''cellos'') or violoncello ( ; ) is a bowed (sometimes plucked and occasionally hit) string instrument of the violin family. Its four strings are usually tuned in perfect fifths: from low to high, C2, G2, ...
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 instrument, single-reed woodwind instrument with a conical body, usually made of brass. As with all single-reed instruments, sound is produced when a reed (mouthpi ...
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 ...
and other brass instruments. The Middle Eastern goblet drum (darbuka) is commonly decorated by mother of pearl.


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, o ...
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 Cr ...
are an elaborate example of this. It is sometimes used in the decorative grips of firearms, and in other gun furniture. 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 place setting, it is used primarily f ...
-like utensils for
caviar Caviar (also known as caviare; from fa, خاویار, khâvyâr, egg-bearing) is a food consisting of salt-cured roe of the family Acipenseridae. Caviar is considered a delicacy and is eaten as a garnish or a spread. Traditionally, the te ...
(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 an artwork such as a painting, sculpture or relief representing a religious subject 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 ...
, , 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 th ...
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 The oldest known tessera ...
,
Topkapı Palace The Topkapı Palace ( tr, Topkapı Sarayı; ota, طوپقپو سرايى, ṭopḳapu sarāyı, lit=cannon gate palace), or the Seraglio, is a large museum in the east of the Fatih district of Istanbul in Turkey. From the 1460s to the compl ...
,
Istanbul ) , postal_code_type = Postal code , postal_code = 34000 to 34990 , area_code = +90 212 (European side) +90 216 (Asian side) , registration_plate = 34 , blank_name_sec2 = GeoTLD , blank_i ...
File:Ile Salomon Pendentif MHNT ETH AC SL 23 Roquemaurel.jpg, Engraved nacre pendant,
Solomon Islands Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its capit ...
1838


Biomedical use

The biotech company Marine Biomedical, formed by a collaboration between the
University of Western Australia The University of Western Australia (UWA) is a public research university in the Australian state of Western Australia. The university's main campus is in Perth, the state capital, with a secondary campus in Albany and various other facilitie ...
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 surgical procedure that replaces missing bone in order to repair bone fractures that are extremely complex, pose a significant health risk to the patient, or fail to heal properly. Some small or acute fractures can be cured wit ...
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 and Tanami deserts in the region of the Pilbara, an ...
, where pearl shells are plentiful, which would grind the nacre into a product fit for use in biomedical products. Future applications could include dental fillings and
spinal surgery Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty concerned with the surgical treatment of disorders which affect any portion of the nervous system including the brain, spinal cord and pe ...
.


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 made of the fossilized shells of ammonites, which in turn are composed primarily of aragonite, the same mineral co ...
*
Pearling in Western Australia Pearling in Western Australia includes the harvesting and farming of both pearls and pearl shells (for mother of pearl) along the north-western coast of Western Australia. The practice of collecting pearl shells existed well before European ...
* Raden


References


Further reading

* * * Checa, Antonio G.; 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