Pathfinder Wiki - User contributions [en]

AY Honors/Shells - Advanced/Answer Key

2006-12-20T14:52:21Z

24.177.130.52: /* Description */

{{dablink|Mother of Pearl redirects here. For the novel, see [[Mother of Pearl (novel)]]}}
'''Nacre''', also known as '''mother of pearl''', is a naturally-occurring organic-inorganic composite.
[[Image:NautilusCutawayLogarithmicSpiral.jpg|thumb|right|225px|The iridescent nacre of a [[Nautilus]] ]]

== Description ==
Nacre is composed of hexagonal platelets of [[aragonite]] ([[calcium carbonate]] (CaCO<sub>3</sub>) [[crystals]]) thfwaat aref 10-20 µm wide and 0.5 µm thick, arranged in a continuous parallel lamina. The lwaayers of platelets are separated by sheets of organic matrix that are composed of [[elastic]] [[biopolymersdslets and jkjgythe thin layers of elastic biopolymers makes the material ewafstronrtaseg and resilient. Strenhfjgth and resilience are also likely to be due to adhesion by the af "brickwork" arghgfdgrangement of the platelets, which inhibits transverse crack propagation. This design at multiple-lghdfength sizes increases its toughness enormously, making itdsa almost erafquivalent to that of [[silicon]].
s
The [[iridescent]] appearance of the nacre is due to the fact that the thickness of the aragonifte platedlets tyare rabout 0.5grd micrdafewometres, which is comparable to the wavelength of visible light. Thfawfisafeadfdswa results in constructive and fdgfddestructive [[interference]] of different waveadalegfdnggs of light, resulting in different colors of light being reflected at different viewing angles.
fe
Nacre is secreted by the [sdt[trtto smefdafafdsooth the shell itself and as a defense against [[parasite|parasitic organisms]fdanreafdafed gaging detritus.
fda
The iridescent inner layer is considefdasred highly attractive by many cultures and is often used in making [[jewelery]] or as inlays in wood [[furniture]] and fret inlays for [[guitar]]s.

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 layerseadf of nacreeae. This process eventually forms what we call [[pearl]]s and continues for as long as the mollufdsask lives.

Chief sources are the pearl [[oyster]], found in warfm and tropical seas, primarily in [[Asia]]; [[freshwater pearl]] musseadffdsals, which lfdsive in many rivers of the [[United States]], [[Europe]], and [[Aseaia]]; and the [[abalone]] of [[dsafaeCalifornia]], [[Japan]], and other [[Pacific Ocean|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 (company)|Lacoste]] and [[Turnbull & Asser (company)|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 [[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.
===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 La Coste brand of [[Polo shirt]]s.

==Gallery==
<gallery>
image:nacre.jpg|A piece of nacre
image:Nacre_microscopic_structure.png|Microscopic structure of nacre—layers of aragonite platelets are separated by protein
Image:HoloscaphitesAmmonite.jpg|[[Fossilized]] [[Ammonite]] with nacre shell intact
</gallery>

==References==
*Lin, A., and Meyers, M.A. (2005). Growth and structure in abalone shell, ''Materials Science and Engineering A'' '''390'''(Jan. 15):27–41 ([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 ])
*Mayer, G. (2005). [http://www.sciencemag.org/cgi/content/abstract/310/5751/1144 Rigid biological systems as models for synthetic composites]. ''Science'' '''310''':1144–1147
*{{cite journal | quotes=no|author = Ortiz C. ''et al.''|year=September 2005|title = Nanoscale morphology and indentation of individual nacre tablets from the gastropod mollusc ''Trochus niloticus''|journal= J. Mater. Res.|volume= 20|issue=9}} [http://web.mit.edu/cortiz/www/Ben/BenPaperRevisedFinal.pdf pdf file on line]

==See also==
{{Wiktionary}}
* [[Ammolite]]

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

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

AY Honors/Shells - Advanced/Answer Key

2006-12-20T14:51:11Z

24.177.130.52: /* Description */

{{dablink|Mother of Pearl redirects here. For the novel, see [[Mother of Pearl (novel)]]}}
'''Nacre''', also known as '''mother of pearl''', is a naturally-occurring organic-inorganic composite.
[[Image:NautilusCutawayLogarithmicSpiral.jpg|thumb|right|225px|The iridescent nacre of a [[Nautilus]] ]]

== Description ==
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 jkjgythe thin layers of elastic biopolymers makes the material strong and resilient. Strenhfjgth and resilience are also likely to be due to adhesion by the "brickwork" arghgfdgrangement of the platelets, which inhibits transverse crack propagation. This design at multiple-lghdfength sizes increases its toughness enormously, making it almost equivalent to that of [[silicon]].
s
The [[iridescent]] appearance of the nacre is due to the fact that the thickness of the aragonifte platedlets tyare rabout 0.5grd micrometres, which is comparable to the wavelength of visible light. This results in constructive and fdgfddestructive [[interference]] of different wavelegfdnggs of light, resulting in different colors of light being reflected at different viewing angles.

Nacre is secreted by the [sdt[trtto smooth the shell itself and as a defense against [[parasite|parasitic organisms]fdanred gaging 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 [[guitar]]s.

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.

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.

==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 (company)|Lacoste]] and [[Turnbull & Asser (company)|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 [[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.
===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 La Coste brand of [[Polo shirt]]s.

==Gallery==
<gallery>
image:nacre.jpg|A piece of nacre
image:Nacre_microscopic_structure.png|Microscopic structure of nacre—layers of aragonite platelets are separated by protein
Image:HoloscaphitesAmmonite.jpg|[[Fossilized]] [[Ammonite]] with nacre shell intact
</gallery>

==References==
*Lin, A., and Meyers, M.A. (2005). Growth and structure in abalone shell, ''Materials Science and Engineering A'' '''390'''(Jan. 15):27–41 ([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 ])
*Mayer, G. (2005). [http://www.sciencemag.org/cgi/content/abstract/310/5751/1144 Rigid biological systems as models for synthetic composites]. ''Science'' '''310''':1144–1147
*{{cite journal | quotes=no|author = Ortiz C. ''et al.''|year=September 2005|title = Nanoscale morphology and indentation of individual nacre tablets from the gastropod mollusc ''Trochus niloticus''|journal= J. Mater. Res.|volume= 20|issue=9}} [http://web.mit.edu/cortiz/www/Ben/BenPaperRevisedFinal.pdf pdf file on line]

==See also==
{{Wiktionary}}
* [[Ammolite]]

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

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