Difference between revisions of "AY Honors/Shells - Advanced/Answer Key"

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'''Byssus''', plural "byssi", derives from [[Hebrew language|Hebrew]] ''būṣ'' 'fine linen,' [[Aramaic]] ''bus'', [[Greek language|Greek]] ''βίσσος'' – 'a very fine yellowish [[flax]] and the [[linen]] woven from it', [[Latin]] ''byssus'' – 'fine [[cotton]] or cotton stuff', '[[silk]]' and via [[New Latin]] to '[[sea silk]]'.
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{{dablink|Mother of Pearl redirects here. For the novel, see [[Mother of Pearl (novel)]] For the moth, see [[Pleuroptya ruralis]]}}
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'''Nacre''', also known as '''mother of pearl''', is a naturally-occurring organic-inorganic composite.
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[[Image:NautilusCutawayLogarithmicSpiral.jpg|thumb|right|225px|The iridescent nacre of a [[Nautilus]] ]]
  
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[[Image: Byssus threads.gif|right|thumbnail|300px|Bussus threads on [[mussel]]s]]
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== Description ==
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Nacre is composed of hexagonal platelets of [[aragonite]] ([[calcium carbonate]] (CaCO<sub>3</sub>) [[crystals]]) that are 10-20 µm wide and 0.5 µm thick, arranged in a continuous parallel lamina. The layers of platelets are separated by sheets of organic matrix that are composed of [[elastic]] [[biopolymers]] (such as [[chitin]], [[lustrin]] and [[silk]]-like proteins). This mixture of brittle platelets and the thin layers of elastic biopolymers makes the material strong and resilient. Strength and resilience are also likely to be due to adhesion by the  "brickwork" arrangement of the platelets, which inhibits transverse crack propagation. This design at multiple-length sizes increases its toughness enormously, making it almost equivalent to that of [[silicon]].
  
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As may be seen above, the word byssus not only refers to the excretions of seashells, as sometimes assumed, but was originally used for various fine threads and cloths.  
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The [[iridescent]] appearance of the nacre is due to the fact that the thickness of the aragonite platelets are about 0.5 micrometres, which is comparable to the wavelength of visible light. This results in constructive and destructive [[interference]] of different wavelengths of light, resulting in different colors of light being reflected at different viewing angles.  
  
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# An exceptionally fine and valuable fibre or cloth of ancient times. Originally used for fine flax and linens, its use was later extended to fine cottons, silks, and sea silk.
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Nacre is secreted by the [[epithelial]] [[cell (biology)|cells]] of the [[Mantle (mollusc)|mantle tissue]] of certain species of [[mollusk]]. In these mollusks, nacre is continually deposited onto the inner surface of the animal's shell (the [[iridescent]] ''nacreous layer'', commonly known as ''mother of pearl''), both as a means to smooth the shell itself and as a defense against [[parasite|parasitic organisms]] and damaging detritus.  
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# The long fine silky [[filament]]s excreted by several [[mollusk]]s (particularly ''Pinna nobilis'') by which they attach themselves to the [[sea bed]], from which [[sea silk]] is manufactured. They range to 6 [[Centimetre|cm]] in length.
 
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# The [[stipe (mycology)|stipe]] (stem) of certain [[fungi]] which are particularly thin and thread-like.
 
  
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==In mussels==
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The iridescent inner layer is considered highly attractive by many cultures and is often used in making [[jewelery]] or as inlays in wood [[furniture]] and fret inlays for  [[guitar]]s.
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Mussels use byssus to attach onto rocks and other surfaces. When a mussel's foot comes across a crevice, it creates a vacuum chamber by forcing out the air and arching up, similar to a plumber's plunger unclogging a drain. In this vacuum chamber, the byssus, made of [[keratin]] and other proteins, is spewed, and bubbles into a sticky foam. By curling its foot into a tube and pumping the foam, the mussel produces sticky threads about the size of a human [[hair]]. It varnishes the threads with another protein to end up with an adhesive.
 
  
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Byssus is a remarkable adhesive in that water does not degrade or deform it as it does with synthetic adhesives. This has spurred [[Genetic engineering|genetic engineers]] to insert mussel [[DNA]] into [[yeast]] cells for translating the genes into the appropriate proteins.
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When a mollusk is invaded by a [[parasite]] or is irritated by a foreign object that the animal cannot eject, a process known as ''[[encystation]]'' entombs the offending entity in successive, concentric layers of nacre. This process eventually forms what we call [[pearl]]s and continues for as long as the mollusk lives.
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Chief sources are the pearl [[oyster]], found in warm and tropical seas, primarily in [[Asia]]; [[freshwater pearl]] mussels, which live in many rivers of the [[United States]], [[Europe]], and [[Asia]]; and the [[abalone]] of [[California]], [[Japan]], and other [[Pacific Ocean|Pacific]] regions.
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 +
==Decorative uses==
 +
 
 +
Both black and white mother of pearl are used for architectural purposes. The natural mother of pearl may be artificially tinted to almost any color.
 +
 
 +
Mother of pearl is also used to clad porcelain sinks. Mother of pearl [[:wikt:tessera|tesserae]] may be cut into artistic shapes and be laminated to ceramic tile and surrounded by numerous coats of colored lacquer to create an artistic design. The lacquer and the mother of pearl are polished at the same time, creating a durable, glossy hard surface.
 +
 
 +
It is also available in thin laminated sheet form, allowing easy inlay and cladding work, and modern ceramic tiles.
 +
 
 +
Shirt buttons were once often made of mother of pearl, though plastic has largely replaced its use.  Some of the finer-quality clothing companies (e.g., [[Lacoste (company)|Lacoste]] and [[Turnbull & Asser (company)|Turnbull & Asser]]) still use it, however.
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 +
Mother of pearl is a popular style watch dial also found in [[Rolex]] watches.
 +
 
 +
Key touches and various decorations on musical instruments such as [[saxophone]]s, [[trumpet]]s, [[violin]]s and [[guitar]]s are sometimes made of mother of pearl.  Synthetic key touches made of [[Pyralin]] or similar imitation materials have been affectionately referred to as ''mother of toilet seat'' by musicians.
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===Tiles===
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Small, hand-cut shapes with straight edges, called '[[:wikt:tessera|tesserae]]', are laminated to either a [[marble]] or a [[ceramic]] 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 1/16 of an inch thick.
 +
 
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===Sheets===
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Instead of using a marble or tile base, the mother of pearl tesserae are glued to a [[fiberglass]] mesh. The result is a lightweight material that offers a seamless installation, and there is no limit to the sheet size. Mother of pearl 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.
 +
 
 +
===Clothes===
 +
It is used as buttons in the popular Lacoste brand of [[Polo shirt]]s.
 +
 
 +
===Guitars===
 +
It is used as inlays on electric guitar fretboards.
 +
 
 +
==Gallery==
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<gallery>
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image:nacre.jpg|A piece of nacre
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image:Nacre_microscopic_structure.png|Microscopic structure of nacre—layers of aragonite platelets are separated by protein
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Image:HoloscaphitesAmmonite.jpg|[[Fossilized]] [[Ammonite]] with nacre shell intact
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</gallery>
  
 
==References==
 
==References==
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* ''The Compact edition of the Oxford English dictionary: complete text reproduced micrographically and Supplement.'' Oxford at the Clarendon Press. 1987
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* {{cite journal
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* ''Webster's Third New International Dictionary (Unabridged)'' 1976. G. & C. Merriam Co.
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| first = A.
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* Ecsedy, Hilda 1975. "Böz – An Exotic Cloth in the Chinese Imperial Court." Hilda Ecsedy. ''Altorientalische Forschungen 3'': pp. 145-153.
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| last = Lin
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* Starr, Cecie and Taggart, Ralph. ''Biology: The Unity and Diversity of Life''. Belmont, CA: Thomson Learning, Inc., 2004.
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| coauthors = Meyers, M.A.
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| date = 2005-01-15
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| title = Growth and structure in abalone shell
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| journal = Materials Science and Engineering A
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| volume = 390
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| pages = 27&ndash;41
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| url = http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TXD-4DH2DRS-1&_coverDate=01%2F15%2F2005&_alid=256050522&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5588&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=f4efd0a3d7cf3b4a0b8f9861cff4514d
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| doi = 10.1016/j.msea.2004.06.072
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}}
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* {{cite journal
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| first = G.
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| last = Mayer
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| year = 2005
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| url = http://www.sciencemag.org/cgi/content/abstract/310/5751/1144
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| title = Rigid biological systems as models for synthetic composites
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| journal = Science
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| volume = 310
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| pages = 1144&ndash;1147
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}}
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* {{cite journal
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| last = Ortiz
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| first = C.
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| coauthors = ''et al.''
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| year = 2005
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| month = September
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| title = Nanoscale morphology and indentation of individual nacre tablets from the gastropod mollusc ''Trochus niloticus''
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| journal = J. Mater. Res.
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| volume = 20
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| issue = 9
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| url = http://web.mit.edu/cortiz/www/Ben/BenPaperRevisedFinal.pdf
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| doi = 10.1557/JMR.2005.0273
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}}
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==See also==
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{{Wiktionary}}
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* [[Ammolite]]
  
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[[Category:Animal anatomy]]
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[[Category:Mollusc products]]
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[[Category:Pearls]]
  
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[[de:Byssus]]
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[[de:Perlmutt]]
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[[es:Biso]]
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[[es:Nácar]]
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[[eo:Bisino]]
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[[eo:Perlamoto]]
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[[it:Bisso]]
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[[fr:Nacre]]
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[[lb:Byssus]]
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[[lt:Perlamutras]]
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[[nl:Byssus]]
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[[nl:Parelmoer]]
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[[pl:Bisior]]
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[[pl:Masa perłowa]]
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[[zh:Byssus]]
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[[pt:Madrepérola]]
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[[sv:Pärlemor]]
 +
[[vi:Xà cừ (vật liệu)]]
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[[tr:Sedef]]

Revision as of 09:10, 20 March 2007

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

The iridescent nacre of a Nautilus

Description

Nacre is composed of hexagonal platelets of aragonite (calcium carbonate (CaCO3) crystals) that are 10-20 µm wide and 0.5 µm thick, arranged in a continuous parallel lamina. The layers of platelets are separated by sheets of organic matrix that are composed of elastic biopolymers (such as chitin, lustrin and silk-like proteins). This mixture of brittle platelets and the thin layers of elastic biopolymers makes the material strong and resilient. Strength and resilience are also likely to be due to adhesion by the "brickwork" arrangement of the platelets, which inhibits transverse crack propagation. This design at multiple-length sizes increases its toughness enormously, making it almost equivalent to that of silicon.

The iridescent appearance of the nacre is due to the fact that the thickness of the aragonite platelets are about 0.5 micrometres, which is comparable to the wavelength of visible light. This results in constructive and destructive interference of different wavelengths of light, resulting in different colors of light being reflected at different viewing angles.

Nacre is secreted by the epithelial cells of the mantle tissue of certain species of mollusk. In these mollusks, nacre is continually deposited onto the inner surface of the animal's shell (the iridescent nacreous layer, commonly known as mother of pearl), both as a means to smooth the shell itself and as a defense against parasitic organisms and damaging detritus.

The iridescent inner layer is considered highly attractive by many cultures and is often used in making jewelery or as inlays in wood furniture and fret inlays for guitars.

When a mollusk is invaded by a parasite or is irritated by a foreign object that the animal cannot eject, a process known as encystation entombs the offending entity in successive, concentric layers of nacre. This process eventually forms what we call pearls and continues for as long as the mollusk lives.

Chief sources are the pearl oyster, found in warm and tropical seas, primarily in Asia; freshwater pearl mussels, which live in many rivers of the United States, Europe, and Asia; and the abalone of California, Japan, and other Pacific regions.

Decorative uses

Both black and white mother of pearl are used for architectural purposes. The natural mother of pearl may be artificially tinted to almost any color.

Mother of pearl is also used to clad porcelain sinks. Mother of pearl tesserae may be cut into artistic shapes and be laminated to ceramic tile and surrounded by numerous coats of colored lacquer to create an artistic design. The lacquer and the mother of pearl are polished at the same time, creating a durable, glossy hard surface.

It is also available in thin laminated sheet form, allowing easy inlay and cladding work, and modern ceramic tiles.

Shirt buttons were once often made of mother of pearl, though plastic has largely replaced its use. Some of the finer-quality clothing companies (e.g., Lacoste and Turnbull & Asser) still use it, however.

Mother of pearl is a popular style watch dial also found in Rolex watches.

Key touches and various decorations on musical instruments such as saxophones, trumpets, violins and guitars are sometimes made of mother of pearl. Synthetic key touches made of Pyralin or similar imitation materials have been affectionately referred to as mother of toilet seat by musicians.

Tiles

Small, hand-cut shapes with straight edges, called 'tesserae', are laminated to either a marble or a ceramic 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 1/16 of an inch thick.

Sheets

Instead of using a marble or tile base, the mother of pearl tesserae are glued to a fiberglass mesh. The result is a lightweight material that offers a seamless installation, and there is no limit to the sheet size. Mother of pearl 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.

Clothes

It is used as buttons in the popular Lacoste brand of Polo shirts.

Guitars

It is used as inlays on electric guitar fretboards.

Gallery

  • A piece of nacre

  • Microscopic structure of nacre—layers of aragonite platelets are separated by protein

  • HoloscaphitesAmmonite.jpg

    Fossilized Ammonite with nacre shell intact

References

See also

Template:Wiktionary

de:Perlmutt es:Nácar eo:Perlamoto fr:Nacre lt:Perlamutras nl:Parelmoer pl:Masa perłowa pt:Madrepérola sv:Pärlemor vi:Xà cừ (vật liệu) tr:Sedef

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