View source for Nacre

{{Short description|Organic-inorganic composite material produced by some molluscs}}
{{Redirect|Mother of pearl}}
{{For|the cloud formation|polar stratospheric cloud}}
[[File:NautilusCutawayLogarithmicSpiral.jpg|thumb|upright=1.2|The iridescent nacre inside a [[nautilus]] shell]]
[[File:Masa perłowa3.jpg|thumb|upright=1.2|Nacreous shell worked into a decorative object]]

'''Nacre''' ({{IPAc-en|ˈ|n|eɪ|k|ər}} {{respell|NAY|kər}}, {{IPAc-en|also|ˈ|n|æ|k|r|ə}} {{respell|NAK|rə}}),<ref>{{cite Dictionary.com|nacre}}</ref> also known as '''mother-of-pearl''', is an organic{{ndash}}inorganic [[composite material]] produced by some [[mollusc]]s as an inner [[seashell|shell]] layer. It is also the material of which [[pearl]]s are composed. It is strong, resilient, and [[Iridescence|iridescent]].

Nacre is found in some of the most ancient lineages of [[bivalve]]s, [[gastropod]]s, and [[cephalopod]]s. However, the inner layer in the great majority of [[mollusc shell]]s is [[Porcelain|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]] pearls.

The outer layer of cultured pearls and the inside layer of [[pearl oyster]] and [[freshwater pearl mussel]] 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]].

==Physical characteristics==

=== Structure and appearance===
{{Further|Structural coloration}}
[[File:Nacre microscopic structure.png|thumb|upright=1.2|Schematic of the microscopic structure of nacre layers]]
[[File:Bruchfläche eines Perlmuttstücks.JPG|thumb|upright=1.2|Electron microscopy image of a fractured surface of nacre]]
{{biomineralization sidebar|exoskeletons}}

Nacre is composed of hexagonal platelets, called tablets, of [[aragonite]] (a form of [[calcium carbonate]]) 10–20&nbsp;[[μm]] wide and 0.5&nbsp;μm thick arranged in continuous parallel [[wikt:lamina|lamina]].<ref name="doi10.1016/j.jsb.2005.09.009"/> Depending on the species, the shape of the tablets differs; in ''[[Pinna (bivalve)|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.<ref>{{Cite book|title=Biominerals and fossils through time|last=Cuif J. P., Dauphin Y., Sorauf J. E.|date=2011|publisher=Cambridge University Press|isbn=978-0-521-87473-1|location=Cambridge|oclc=664839176}}</ref> These layers are separated by sheets of organic matrix (interfaces) composed of [[Elasticity (physics)|elastic]] [[biopolymers]] (such as [[chitin]], [[Lustrin A|lustrin]] and [[silk]]-like [[protein]]s).

Nacre appears [[Iridescence|iridescent]] because the thickness of the aragonite platelets is close to the wavelength of visible [[light]]. These structures [[interference (wave propagation)|interfere]] constructively and destructively  with different wavelengths of light at different viewing angles, creating [[Structural coloration|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.<ref name='Metzler2007'/><ref name='Olson2012'/>  In bivalves and cephalopods, the ''b-''axis points in the direction of shell growth, whereas in the [[monoplacophora]] it is the ''a''-axis that is inclined this way.<ref name=Checa2009/>

=== 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]] of 70&nbsp;[[Pascal (unit)|GPa]] and a yield stress of roughly 70 MPa (when dry).<ref name="Jackson1988" /> 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]], making it almost as strong as [[silicon]].<ref name="Gim2019" /> The mineral–organic interface results in enhanced resilience and strength of the organic interlayers.<ref name="r2" /><ref name="r3" /><ref name="r4" /> The interlocking of bricks of nacre has large impact on both the deformation mechanism as well as its toughness.<ref name="r1" />  [[Tensile testing|Tensile]], [[Shear stress|shear]], and compression tests, [[Weibull distribution|Weibull]] analysis, [[nanoindentation]], and other techniques have all been used to probe the mechanical properties of nacre.<ref name=":0">{{Cite journal |last1=Sun |first1=Jiyu |last2=Bhushan |first2=Bharat |date=2012-08-14 |title=Hierarchical structure and mechanical properties of nacre: a review |journal=RSC Advances |language=en |volume=2 |issue=20 |pages=7617–7632 |doi=10.1039/C2RA20218B |bibcode=2012RSCAd...2.7617S |issn=2046-2069|doi-access=free }}</ref> Theoretical and computational methods have also been developed to explain the experimental observations of nacre's mechanical behavior.<ref>{{Cite journal |last1=Ji |first1=Baohua |last2=Gao |first2=Huajian |date=2004-09-01 |title=Mechanical properties of nanostructure of biological materials |url=https://www.sciencedirect.com/science/article/pii/S0022509604000705 |journal=Journal of the Mechanics and Physics of Solids |language=en |volume=52 |issue=9 |pages=1963–1990 |doi=10.1016/j.jmps.2004.03.006 |bibcode=2004JMPSo..52.1963J |issn=0022-5096|url-access=subscription }}</ref><ref name=":1">{{Cite journal |last1=Okumura |first1=K. |last2=de Gennes |first2=P.-G. |date=2001-01-01 |title=Why is nacre strong? Elastic theory and fracture mechanics for biocomposites with stratified structures |journal=The European Physical Journal E |language=en |volume=4 |issue=1 |pages=121–127 |doi=10.1007/s101890170150 |bibcode=2001EPJE....4..121O |s2cid=55616061 |issn=1292-8941}}</ref> Nacre is stronger under [[Compressive stress|compressive]] loads than [[tensile]] ones when the force is applied parallel or perpendicular to the platelets.<ref name=":0" /> As an oriented structure, nacre is highly [[Anisotropy|anisotropic]] 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.<ref name=":0" /> In [[laminated]] structures with hard and soft layers, a model system that can be applied to understand nacre, the [[fracture]] energy and fracture strength are both larger than those values characteristic of the hard material only.<ref name=":1" /> Specifically, this structure facilitates crack deflection, since it is easier for the crack to continue into the [[Viscoelasticity|viscoelastic]] and compliant organic matrix than going straight into another aragonite platelet.<ref name=":0" /><ref name=":2">{{Cite journal |last1=Feng |first1=Q. L. |last2=Cui |first2=F. Z. |last3=Pu |first3=G. |last4=Wang |first4=R. Z. |last5=Li |first5=H. D. |date=2000-06-30 |title=Crystal orientation, toughening mechanisms and a mimic of nacre |journal=Materials Science and Engineering: C |language=en |volume=11 |issue=1 |pages=19–25 |doi=10.1016/S0928-4931(00)00138-7 |issn=0928-4931|doi-access=free }}</ref> This results in the [[Ductility|ductile]] protein phase deforming such that the crack changes directions and avoids the [[Brittleness|brittle]] ceramic phase.<ref name=":0" /><ref name=":3">{{Cite journal |last1=Grossman |first1=Madeleine |last2=Pivovarov |first2=Dmitriy |last3=Bouville |first3=Florian |last4=Dransfeld |first4=Clemens |last5=Masania |first5=Kunal |last6=Studart |first6=André R. |date=February 2019 |title=Hierarchical Toughening of Nacre-Like Composites |journal=Advanced Functional Materials |language=en |volume=29 |issue=9 |article-number=1806800 |doi=10.1002/adfm.201806800 |s2cid=139307131 |issn=1616-301X|doi-access=free }}</ref> Based on experiments done on nacre-like [[Chemical synthesis|synthetic materials]], it is hypothesized that the compliant matrix needs to have a larger fracture energy than the [[elastic energy]] at fracture of the hard phase.<ref name=":3" /> [[Fiber pull-out]], which occurs in other ceramic [[composite material]]s,  contributes to this phenomenon.<ref name=":2" /> 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]] of the ceramic phase to the organic one, but also by these connecting [[nanoscale]] features.<ref name=":2" /><ref name=":0" /> As plastic deformation starts, the [[mineral bridge]]s may break, creating small asperities that roughen the aragonite-protein interface.<ref name=":0" /> The additional friction generated by the asperities helps the material withstand shear stresses.<ref name=":0" /> In nacre-like composites, the mineral bridges have also been shown to increase the [[flexural strength]] of the material because they can transfer stress in the material.<ref>{{Cite journal |last1=Magrini |first1=Tommaso |last2=Moser |first2=Simon |last3=Fellner |first3=Madeleine |last4=Lauria |first4=Alessandro |last5=Bouville |first5=Florian |last6=Studart |first6=André R. |date=2020-05-20 |title=Transparent Nacre-like Composites Toughened through Mineral Bridges |journal=Advanced Functional Materials |volume=30 |issue=27 |article-number=2002149 |doi=10.1002/adfm.202002149 |s2cid=219464365 |issn=1616-301X|hdl=20.500.11850/417234 |hdl-access=free }}</ref> 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 "[[Brickwork|brick-and-mortar]]" structure, mineral bridges, and other hierarchical features.

When dehydrated, nacre loses much of its strength and acts as a brittle material, like pure aragonite.<ref name=":0" /> The hardness of this material is also negatively impacted by dehydration.<ref name=":0" /> Water acts as a [[plasticizer]] for the organic matrix, improving its toughness and reducing its shear modulus.<ref name=":0" /> Hydrating the protein layer also decreases its [[Young's modulus]], which is expected to improve the fracture energy and strength of a composite with alternating hard and soft layers.<ref name=":1" />

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.<ref name="Abid2018" /> However, the negative effects of statistical variations can be offset by interfaces with large strain at failure accompanied by strain hardening.<ref name="Abid2018" /> On the other hand, the [[fracture toughness]] of nacre increases with moderate statistical variations which creates tough regions where the crack gets pinned.<ref name="Abid2019" /> But, higher statistical variations generates very weak regions which allows the crack to propagate without much resistance causing the fracture toughness to decrease.<ref name="Abid2019" /> Studies have shown that this weak structural defects act as dissipative topological defects coupled by an elastic distortion.<ref name="Beliaev2021" />

===Formation===
The process of how nacre is formed is not completely clear. It has been observed in ''[[Pinna nobilis]]'', 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.<ref name='Hovden2015'/> 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.<ref name=Jackson2010/> 

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.<ref name='Checa2009'/> This produces the hexagonal close-packing characteristic of nacre.<ref name='Checa2009'/> The growth of these bricks can be initiated in various ways such as from randomly scattered elements within the organic layer,<ref name=r5/> well-defined arrangements of proteins,<ref name="doi10.1016/j.jsb.2005.09.009"/> or they may expand from mineral bridges coming from the layer underneath.<ref name='Schaffer1997'/><ref name='Checa2011'/> 

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.<ref name=b1/>

A 2021 paper in ''[[Nature Physics]]'' examined nacre from ''[[Unio pictorum]]'', 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.<ref name=Beliaev2021/><ref>{{cite news |last=Meyers |first=Catherine |date=January 11, 2021 |title=How Mollusks Make Tough, Shimmering Shells |url=https://www.insidescience.org/news/how-mollusks-make-tough-shimmering-shells |work=Inside Science |access-date=June 9, 2021}}</ref>

===Function===
[[File:Fossil nautiloid shell with original iridescent nacre in fossiliferous asphaltic limestone.jpg|thumb|upright=1.2|Fossil [[nautiloid]] shell with original iridescent nacre in fossiliferous asphaltic limestone, [[Oklahoma]]. Dated to the [[Pennsylvanian (geology)|late Middle Pennsylvanian]], which makes it by far the oldest deposit in the world with aragonitic nacreous shelly fossils.<ref>{{Cite AV media|last=John|first=James St|title=Fossil nautiloid shell with original iridescent nacre in fossiliferous asphaltic limestone (Buckhorn Asphalt, Middle Pennsylvanian; Buckhorn Asphalt Quarry, Oklahoma, USA) 1|date=2007-07-31|url=https://www.flickr.com/photos/jsjgeology/15054496278/|access-date=2023-01-09|via=Flickr |type=photo}}</ref>]]
Nacre is secreted by the [[epithelial]] [[cell (biology)|cells]] of the [[Mantle (mollusc)|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]]s and damaging debris by entombing them in successive layers of nacre, forming either a blister [[pearl]] 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===
{{Further|Mollusc shell#Evolution}}

The form of nacre varies from group to group. In [[bivalves]], the nacre layer is formed of single crystals in a [[hexagonal close packed|hexagonal close packing]].  In [[gastropods]], crystals are [[twinned crystal|twinned]], and in [[cephalopods]], they are pseudohexagonal monocrystals, which are often twinned.<ref name=Checa2009/>

==Commercial sources==
[[File:Nacre sticks.JPG|thumb|upright=1.2|Nacre bracelet]]

The main commercial sources of mother-of-pearl have been the [[pearl oyster]], [[freshwater pearl]] mussels, and to a lesser extent the [[abalone]], 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]]'' 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]], an agreement signed by more than 170 countries.<ref>{{Cite web|author=Jessica Hodin
|date=October 19, 2010|title=Contraband Chic: Mother-of-Pearl Items Sell With Export Restrictions |website=[[The New York Observer]] |url=http://www.observer.com/2010/culture/contraband-chic-mother-pearl-items-sell-export-restrictions|access-date=2023-01-09|archive-url=https://web.archive.org/web/20101024213824/http://www.observer.com/2010/culture/contraband-chic-mother-pearl-items-sell-export-restrictions |archive-date=2010-10-24 }}</ref>

==Uses==
{{sea shell topics}}

===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.{{citation needed|date=May 2025}}

====Architecture====
Both black and white nacre are used for [[architectural]] purposes. The natural nacre may be artificially tinted to almost any color. Nacre [[:wikt:tessera|tesserae]] may be cut into shapes and [[lamination|laminated]] to a [[ceramic]] [[tile]] or [[marble]] 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 {{convert|2|mm|in}} thick.  The tesserae are then [[lacquer]]ed and [[polishing|polished]] creating a durable and glossy surface. Instead of using a marble or tile base, the nacre tesserae can be glued to [[fiberglass]]. 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.{{citation needed|date=March 2014}}

'''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 [[Abalone|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.<ref>{{Cite web |title=Different Pearl Types & Colors {{!}} The Four Major Types of Cultured Pearls {{!}} GIA |url=https://www.gia.edu/pearl-description |archive-url=https://web.archive.org/web/20250402014826/https://www.gia.edu/pearl-description |archive-date=2025-04-02 |access-date=2025-04-11 |website=www.gia.edu |language=en |url-status=live }}</ref>

====Musical instruments====
Nacre inlay is often used for music [[Key (instrument)|keys]] and other decorative motifs on musical instruments. Many [[accordion]] and [[concertina]] bodies are completely covered in nacre, and some [[guitar]]s have fingerboard or headstock inlays made of nacre (or imitation [[pearloid]] plastic inlays). The [[bouzouki]] and [[baglamas]] (Greek plucked string instruments of the [[lute]] family) typically feature nacre decorations, as does the related Middle Eastern [[oud]] (typically around the [[sound hole]]s and on the back of the instrument). [[bow (music)|Bows]] of stringed instruments such as the [[violin]] and [[cello]] often have mother-of-pearl inlay at the frog. It is traditionally used on [[saxophone]] keytouches, as well as the valve buttons of [[trumpets]] and other brass instruments. The Middle Eastern [[goblet drum]] (darbuka) is commonly decorated by mother-of-pearl.{{citation needed|date=December 2021}}

====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]]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]] in 1924, he received a gold medal.<ref name="Anukul Charan Munshi, the Maverick of Indian Mother-of-Pearl Artistry">{{cite news |title= Anukul Charan Munshi, the Maverick of Indian Mother-of-Pearl Artistry|url=https://webbio257.wixsite.com/anukulcharanmunshith |publisher=Wixsite.com |date=February 5, 2005 |access-date=Sep 22, 2022 |location=Calcutta, India}}</ref><ref name="Anukul Charan Munshi">{{cite news |title= Anukul Charan Munshi|url=https://arthive.com/artists/97278~Anukul_Charan_Munshi |publisher=Arthive |date=February 5, 2005 |access-date=Sep 22, 2022 |location=Calcutta, India}}</ref> His eldest son [[Annada Munsi|Annada Munshi]] is credited with drawing ''Indian Swadesi Movement'' in the form of Indian advertising.<ref>{{Cite web |url=https://www.researchgate.net/figure/Poster-by-Annada-Munshi-for-ITMEB-1947-courtesy-Courtesy-Urban-History-Documentation_fig8_274463295 |title=Poster by Annada Munshi for ITMEB, 1947 |work=Urban History Documentation Archive, Centre for Studies in Social Sciences, Calcutta |via=ResearchGate |date= |access-date=24 December 2023}}</ref> Anukul Charan Munshi's third son [[Manu Munsi| 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]], Dr. [[Bidhan Chandra Roy]], sent Manu's artwork, "Gandhiji's Noakhali Abhiyan", to the [[United States]]. Numerous illustrious figures, such as [[Satyajit Ray]], [[Bidhan Chandra Roy]], Barrister Subodh Chandra Roy, [[Subho Tagore]], [[Humayun Kabir (Bengal politician)|Humayun Kabir]], [[Jehangir Kabir]], as well as his elder brother Annada Munshi, were among the patrons of his works of art. "[[Indira Gandhi]]" 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.<ref name="Anandabazar Patrika: Munshiana">Anandabazar Patrika. "Munshiana" Publisher: [[Anandabazar Patrika]]</ref><ref name="Artist Manu Munshi">{{cite news |title=Artist Manu Munshi, Renowned Mother of Pearl Artist of India |url=https://srijonmunshi930.wixsite.com/artistmanumunshi |publisher=Wixsite.com |date=February 5, 2005 |access-date=Sep 22, 2022 |location=Calcutta, India}}</ref>  His cousin Pratip Munshi was also a famed mother-of-pearl artist.<ref name="Santanu Ghosh: Binodane Paikpara Belgachia">{{cite web |author=Santanu Ghosh 
|url=https://thecafetable.com/binodane_paikpara_belgachia |title=Binodane Paikpara Belgachia |publisher=Dey's Publishing |date= |access-date=24 December 2023}}</ref><ref name="Santanu Ghosh: Munshianay Chollis Purush">Santanu Ghosh. "Munshianay Chollis Purush" Publisher: Dey's Publishing</ref>

====Other ====
Mother-of-pearl [[button]]s are used in clothing either for functional or decorative purposes. The [[Pearly Kings and Queens]] are an elaborate example of this.{{Citation needed|date=April 2025}}

Mother-of-pearl is sometimes used to make [[spoon]]-like utensils for [[caviar]] (i.e. caviar servers<ref>{{Cite web |title=Ceto the Shrimp - Plate |url=https://www.objetluxe.com/product/ceto-the-shrimp/ |access-date=2021-07-14 |website=Objet Luxe }}</ref><ref>{{Cite web |title=Crab Caviar Server |url=https://www.objetluxe.com/product/caviar-server/ |archive-url=https://web.archive.org/web/20210513005709/https://www.objetluxe.com/product/caviar-server/ |archive-date=May 13, 2021 |access-date=2021-07-14 |website=Objet Luxe }}</ref>) so as to not spoil the taste with metallic spoons.

<gallery mode="packed" heights="160px" style="float:left">
File:Flügelretabel Perlmutt Augsburg um 1520.jpg | [[Altarpiece]], {{circa|1520}}, with extensive use of carved nacre
File:Powder flask img 2091.jpg | Nacre [[powder flask|gunpowder flask]], {{circa|1750}}, mostly made of ''[[Turbo marmoratus]]'' shell
File:Istanbul.Topkapi046.jpg | [[Inlay]] with nacre [[tesserae]], [[Topkapı Palace]], [[Istanbul]]
File:Ile Salomon Pendentif MHNT ETH AC SL 23 Roquemaurel.jpg | Engraved nacre pendant, [[Solomon Islands]] 1838
File:CaviarSpoonSilverEngravedHandle.jpg|Mother-of-pearl [[caviar spoon]] with [[sterling silver]] handle

File:Train photo enhanced with mother of pearl.jpg|Train photo enhanced with mother of pearl.  Made for display in the office of E. J. Gorman, president of the Chicago, Rock Island & Pacific RR.  Now at the Western Trails Museum, [[Knott's Berry Farm]], Buena Park, CA.
</gallery>
{{clear left}}

== Manufactured nacre ==
In 2012, researchers created calcium-based nacre in the laboratory by mimicking its natural growth process.<ref>{{cite journal  |doi=10.1038/ncomms1970|pmid=22828626|title=Biomimetic layer-by-layer assembly of artificial nacre|year=2012|last1=Finnemore|first1=Alexander|last2=Cunha|first2=Pedro|last3=Shean|first3=Tamaryn|last4=Vignolini|first4=Silvia|last5=Guldin|first5=Stefan|last6=Oyen|first6=Michelle|last7=Steiner|first7=Ullrich|journal=Nature Communications|volume=3|page=966|bibcode=2012NatCo...3..966F|s2cid=9004843 |url=http://discovery.ucl.ac.uk/1446952/1/nacrenatureV8.pdf}}</ref>

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.<ref>{{cite web|url=http://www.gizmag.com/mollusk-nacre-tougher-glass/30654 |title=Super-tough glass based on mollusk shells |date=30 January 2014 |publisher=Gizmag.com |access-date=2014-02-13}}</ref>

==See also==
* [[Ammolite]]
* [[Mother-of-pearl carving in Bethlehem]]
* [[Pearling in Western Australia]]
* [[Raden]]

==References==

{{Reflist|35em|refs=
<ref name=Jackson2010>{{cite journal|doi=10.1093/molbev/msp278|title=Parallel Evolution of Nacre Building Gene Sets in Molluscs|year=2009|last1=Jackson|first1=D. J.|last2=McDougall|first2=C.|last3=Woodcroft|first3=B.|last4=Moase|first4=P.|last5=Rose|first5=R. A.|last6=Kube|first6=M.|last7=Reinhardt|first7=R.|last8=Rokhsar|first8=D. S.|last9=Montagnani|first9=C.|last10=Joubert|first10=C.|last11=Piquemal|first11=D.|last12=Degnan|first12=B. M.|journal=Molecular Biology and Evolution|volume=27|issue=3|pages=591–608|pmid=19915030|display-authors=8|doi-access=free}}</ref>

<ref name=Jackson1988>
{{cite journal
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| last2 = Vincent | first2 = J. F. V
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| publication-date = 22 Sep 1988
| title = The mechanical design of nacre
| jstor = 36211
| journal = Proceedings of the Royal Society B: Biological Sciences
| volume = 234 | issue = 1277 | pages = 415–440
| doi = 10.1098/rspb.1988.0056 
| year = 1988
| bibcode = 1988RSPSB.234..415J
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</ref>

<ref name=Abid2018>
{{cite journal
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| last2 = Mirkhalaf | first2 = M.
| last3 = Barthelat | first3 = F.
| publication-date = 2018
| title = Discrete-element modeling of nacre-like materials: effects of random microstructures on strain localization and mechanical performance
| journal = Journal of the Mechanics and Physics of Solids
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<ref name=Abid2019>
{{cite journal
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| last2 = Pro | first2 = J. W.
| last3 = Barthelat | first3 = F.
| publication-date = 2019
| title = Fracture mechanics of nacre-like materials using discrete-element models: Effects of microstructure, interfaces and randomness
| journal = Journal of the Mechanics and Physics of Solids
| volume = 124 | pages = 350–365
| doi = 10.1016/j.jmps.2018.10.012
| year = 2019
| bibcode = 2019JMPSo.124..350A
| s2cid = 139839008
}}
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<ref name=Beliaev2021>
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| publication-date = 2021
| title = Dynamics of topological defects and structural synchronization in a forming periodic tissue
| journal = Nature Physics
| volume = 124 | pages = 350–365
| doi = 10.1038/s41567-020-01069-z
| year = 2021
| issue = 3
| bibcode = 2021NatPh..17..410B
| s2cid = 230508602
}}
</ref>

<ref name='Checa2009'>{{cite journal|doi = 10.1007/s00114-008-0461-1|title = Nacre and false nacre (foliated aragonite) in extant monoplacophorans (=Tryblidiida: Mollusca)|year = 2008|last1 = Checa|first1 = Antonio G.|last2 = Ramírez-Rico|first2 = Joaquín|last3 = González-Segura|first3 = Alicia|last4 = Sánchez-Navas|first4 = Antonio|journal = Naturwissenschaften|volume = 96|pages = 111–22|pmid = 18843476|issue = 1 | bibcode=2009NW.....96..111C |s2cid = 10214928}}</ref>

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<ref name=r3>{{cite journal|doi=10.1016/j.mechrescom.2007.09.006|title=Experimental investigation of nanomechanics of the mineral-protein interface in nacre|year=2008|last1=Mohanty|first1=Bedabibhas|last2=Katti|first2=Kalpana S.|last3=Katti|first3=Dinesh R.|journal=Mechanics Research Communications|volume=35|issue=1–2|page=17}}</ref>

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<ref name='Schaffer1997'>{{cite journal|doi=10.1021/cm960429i|title=Does abalone nacre form by heteroepitaxial nucleation or by growth through mineral bridges?|year=1997|last1=Schäffer|first1=Tilman|last2=Ionescu-Zanetti|first2=Cristian|last3=Proksch|first3=Roger|last4=Fritz|first4=Monika|last5=Walters|first5=Deron|last6=Almquist|first6=Nils|last7=Zaremba|first7=Charlotte|last8=Belcher|first8=Angela|last9=Smith|first9=Bettye|last10=Stucky|first10=Galen|journal=Chemistry of Materials|volume=9|issue=8|pages=1731–1740|url=http://ltu.diva-portal.org/smash/get/diva2:986717/FULLTEXT01}}</ref>

<ref name='Gim2019'>{{cite journal |doi=10.1038/s41467-019-12743-z |title=Nanoscale deformation mechanics reveal resilience in nacre of Pinna nobilis shell|year=2019|last1=Gim|first1=J|last2=Schnitzer|first2=N|last3=Otter|first3=Laura|journal=Nature Communications|volume=10|issue=1|page=4822|pmid=31645557|pmc=6811596|arxiv=1910.11264|bibcode=2019NatCo..10.4822G|doi-access=free}}</ref>

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}}

==Further reading==
* {{cite journal
| last1 = Abid
| first1 = N.
| year = 2018
| title = Discrete-element modeling of nacre-like materials: Effects of random microstructures on strain localization and mechanical performance
| journal = Journal of the Mechanics and Physics of Solids
| volume = 112
| doi = 10.1016/j.jmps.2017.11.003
| pages = 385–402
| last2 = Mirkhalaf
| first2 = M.
| last3 = Barthelat
| first3 = F.| bibcode = 2018JMPSo.112..385A
}}
* {{cite journal
| last1 = Bruet
| first1 = B.
| year = 2005
| title = Nanoscale morphology and indentation of individual nacre tablets from the gastropod mollusc ''Trochus niloticus''
| journal = J. Mater. Res.
| volume = 20
| issue = 9
| url = http://web.mit.edu/cortiz/www/Ben/BenPaperRevisedFinal.pdf
| doi = 10.1557/JMR.2005.0273
| page = 2400
| last2 = Qi
| first2 = H.J.
| last3 = Boyce
| first3 = M.C.
| last4 = Panas
| first4 = R.
| last5 = Tai
| first5 = K.
| last6 = Frick
| first6 = L.
| last7 = Ortiz
| first7 = C.| bibcode = 2005JMatR..20.2400B
| s2cid = 564507
}}
* Checa, Antonio G.; [[Julyan Cartwright|Julyan H. E. Cartwright]], Marc-Georg Willinger and Steven M. Stanley (Jan. 6, 2009), [https://www.pnas.org/content/106/1/38 "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. {{doi|10.1073/pnas.0808796106}}.
* {{cite journal |last1 = Frýda |first1 = J. |last2 = Bandel |first2 = K. |last3 = Frýdová |first3 = B. |year = 2009 | title = Crystallographic texture of Late Triassic gastropod nacre: evidence of long-term stability of the mechanism controlling its formation | journal = [[Bulletin of Geosciences]] | volume = 84 | issue = 4| pages = 745–754 | doi = 10.3140/bull.geosci.1169 | doi-access = free }}
* {{cite journal
| first = A.
| last = Lin
|author2=Meyers, M.A.
| date = 2005-01-15
| title = Growth and structure in abalone shell
|journal = Materials Science and Engineering A
| volume = 390
| issue = 1–2
| pages = 27–41
| doi = 10.1016/j.msea.2004.06.072
}}
* {{cite journal
| first = G.
| last = Mayer
| year = 2005
| doi =  10.1126/science.1116994
| title = Rigid biological systems as models for synthetic composites
| journal = Science
| volume = 310
| pages = 1144–1147
| pmid = 16293751
| issue = 5751
| bibcode = 2005Sci...310.1144M
| s2cid = 19079526
}}

==External links==
{{Commons category|Nacre}}
{{Wiktionary}}
* [https://statenisland.pastperfectonline.com/search?utf8=%E2%9C%93&search_criteria=mother-of-pearl&searchButton=Search Objects with mother-of-pearl in the Staten Island Historical Society Online Collections Database]

{{Bivalve anatomy}}
{{Cephalopod anatomy}}
{{Gastropod anatomy}}
{{Jewellery}}
{{Authority control}}

[[Category:Mollusc products]]
[[Category:Pearls]]
[[Category:Mollusc anatomy]]