Difference between revisions of "Aragonite"

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[[File:1993.818-SC36608.jpg|thumb|]]
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[[File:1993.818-SC36608.jpg|thumb|Lizard effigy vase<br>MFA# 1993.818]]
 
== Description ==
 
== Description ==
  
 
A crystalline form of [[calcium%20carbonate|calcium carbonate]] that occurs in [[coral|coral]], [[seashell|shells]], [[pearl|pearls]], stalactites, and water deposits. Aragonite was named after the Aragon region in Spain where it was first discovered. Its orthorhombic system forms compact, acicular crystals that make it harder and heavier than [[calcite|calcite]]. When aragonite is formed by water deposition of calcium carbonate, the crystals often grow in radiating flowers. Aragonite mines are located in Europe, Bolivia, and the U.S. (New Mexico, Arizona). Aragonite was used in antiquity for beads and decorative items. It can be converted to calcite with heat (470 C) and changes slowly to calcite at room temperature.
 
A crystalline form of [[calcium%20carbonate|calcium carbonate]] that occurs in [[coral|coral]], [[seashell|shells]], [[pearl|pearls]], stalactites, and water deposits. Aragonite was named after the Aragon region in Spain where it was first discovered. Its orthorhombic system forms compact, acicular crystals that make it harder and heavier than [[calcite|calcite]]. When aragonite is formed by water deposition of calcium carbonate, the crystals often grow in radiating flowers. Aragonite mines are located in Europe, Bolivia, and the U.S. (New Mexico, Arizona). Aragonite was used in antiquity for beads and decorative items. It can be converted to calcite with heat (470 C) and changes slowly to calcite at room temperature.
  
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[[File:36.178-20-3.jpg|thumb|]]
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[[File:Shell trumpet.jpg|thumb|Shell trumpet<br>MFA# 17.2170]]
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== Synonyms and Related Terms ==
 
== Synonyms and Related Terms ==
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calcium carbonate; nacre; shell white; coral; Aragonit (Deut., Pol.); aragonita (Esp.); aragonito (Esp.); aragonite (Fr., Port.); aragoniet (Ned.)
 
calcium carbonate; nacre; shell white; coral; Aragonit (Deut., Pol.); aragonita (Esp.); aragonito (Esp.); aragonite (Fr., Port.); aragoniet (Ned.)
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[[[SliderGallery rightalign|Aragonite 2.TIF~FTIR (MFA)|Aragonite (HU Min. Museum 116189), 50X, 785 nm copy.tif~Raman (MFA)|aragonite.jpg~Chemical structure]]]
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== Risks ==
  
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[[[SliderGallery rightalign|Aragoniteitaly1.jpg~Raman|MFA- Aragonite.jpg~FTIR|aragonite.jpg~Chemical structure]]]
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* No significant hazards. 
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* ThermoFisher: [https://www.fishersci.com/store/msds?partNumber=AC423510025&productDescription=CALCIUM+CARBONATE+99%2BACS+2.5KG&vendorId=VN00032119&countryCode=US&language=en SDS]
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== Other Properties ==
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== Physical and Chemical Properties ==
  
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Orthorhombic crystal system with platy or fibrous, acicular crystals that are often twinned.  Reacts with acids to evolve carbon dioxide.  Fluorescent.  Brittle.  Aragonite is harder and denser than calcite.   
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* Orthorhombic crystal system with platy or fibrous, acicular crystals that are often twinned
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* Reacts with acids to evolve carbon dioxide.   
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Luster = vitreous to resinous.  Transparent to translucent.  Fracture = subconchoidal. Streak = white  
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* Aragonite is harder and denser than calcite.   
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* Fracture = subconchoidal, brittle
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Strongly birefringent showing interference colors.  Straight extinction
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* Luster = vitreous to resinous  
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* Transparent to translucent   
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* Streak = white  
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* Fluorescence = variable
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* Birefringence = strong showing interference colors
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* Straight extinction
  
 
{| class="wikitable"
 
{| class="wikitable"
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! scope="row"| Composition
 
! scope="row"| Composition
 
| CaCO3
 
| CaCO3
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|-
 
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! scope="row"| CAS
 
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| 471-34-1
 
 
|-
 
|-
 
! scope="row"| Mohs Hardness
 
! scope="row"| Mohs Hardness
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|-
 
|-
 
! scope="row"| Density
 
! scope="row"| Density
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| 2.93-2.95
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| 2.93-2.95 g/ml
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|-
 
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! scope="row"| Molecular Weight
 
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| mol. wt. = 100.09
 
 
|-
 
|-
 
! scope="row"| Refractive Index
 
! scope="row"| Refractive Index
 
| 1.530, 1.682, 1.686
 
| 1.530, 1.682, 1.686
 
|}
 
|}
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== Hazards and Safety ==
 
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No significant hazards. 
 
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Mallinckrodt Baker: [http://www.jtbaker.com/msds/englishhtml/c0330.htm MSDS]
 
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== Additional Information ==
 
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° R. Gettens, E. West Fitzhugh, R.Feller, "Calcium Carbonate Whites", ''Artists Pigments'', Vol. 2., A. Roy ed. Oxford University Press, Oxford, 1993.
 
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° Mineralogy Database: [http://www.webmineral.com/data/Aragonite.shtml Aragonite]
 
  
 
== Additional Images ==
 
== Additional Images ==
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File:Aragoniteemr.jpg|Aragonite
 
File:Aragoniteemr.jpg|Aragonite
 
File:pa20720aragonite.jpg|Aragonite
 
File:pa20720aragonite.jpg|Aragonite
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File:36.178-20-3.jpg|Stamp seal<br>MFA# 36.178
 
</gallery>
 
</gallery>
  
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== Resources and Citations ==
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* R. Gettens, E. West Fitzhugh, R.Feller, "Calcium Carbonate Whites", ''Artists Pigments'', Vol. 2., A. Roy ed. Oxford University Press, Oxford, 1993.
  
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== Authority ==
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* Mineralogy Database: [http://www.webmineral.com/data/Aragonite.shtml Aragonite]
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* Jack Odgen, ''Jewellery of the Ancient World'', Rizzoli International Publications Inc., New York City, 1982
 
* Jack Odgen, ''Jewellery of the Ancient World'', Rizzoli International Publications Inc., New York City, 1982
  
 
* Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, ''Pigment Compendium'', Elsevier Butterworth-Heinemann, Oxford, 2004  Comment: Refractive Index: alpha=1.529-1.530; beta=1.680-1.682; gamma=1.685-1.686
 
* Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, ''Pigment Compendium'', Elsevier Butterworth-Heinemann, Oxford, 2004  Comment: Refractive Index: alpha=1.529-1.530; beta=1.680-1.682; gamma=1.685-1.686
  
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* ''Encyclopedia Britannica'', http://www.britannica.com  Comment: aragonite" Encyclopædia Britannica [Accessed December 4, 2001
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* ''Encyclopedia Britannica'', http://www.britannica.com  Comment: aragonite" [Accessed December 4, 2001
  
 
* C.W.Chesterman, K.E.Lowe, ''Audubon Society Field Guide to North American Rocks and Minerals'', Alfred A. Knopf, New York, 1979
 
* C.W.Chesterman, K.E.Lowe, ''Audubon Society Field Guide to North American Rocks and Minerals'', Alfred A. Knopf, New York, 1979
  
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* Wikipedia, the free encyclopedia, at http://www.wikipedia.com  Comment: http://en.wikipedia.org/wiki/Aragonite (Accessed Aug. 30 2005)
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* Wikipedia: http://en.wikipedia.org/wiki/Aragonite (Accessed Aug. 30 2005)
  
 
* G.S.Brady, ''Materials Handbook'', McGraw-Hill Book Co., New York, 1971  Comment: p. 131
 
* G.S.Brady, ''Materials Handbook'', McGraw-Hill Book Co., New York, 1971  Comment: p. 131

Latest revision as of 10:28, 17 December 2022

Lizard effigy vase
MFA# 1993.818

Description

A crystalline form of Calcium carbonate that occurs in Coral, shells, pearls, stalactites, and water deposits. Aragonite was named after the Aragon region in Spain where it was first discovered. Its orthorhombic system forms compact, acicular crystals that make it harder and heavier than Calcite. When aragonite is formed by water deposition of calcium carbonate, the crystals often grow in radiating flowers. Aragonite mines are located in Europe, Bolivia, and the U.S. (New Mexico, Arizona). Aragonite was used in antiquity for beads and decorative items. It can be converted to calcite with heat (470 C) and changes slowly to calcite at room temperature.

Shell trumpet
MFA# 17.2170

Synonyms and Related Terms

calcium carbonate; nacre; shell white; coral; Aragonit (Deut., Pol.); aragonita (Esp.); aragonito (Esp.); aragonite (Fr., Port.); aragoniet (Ned.)

FTIR (MFA)

Aragonite 2.TIF

Raman (MFA)

Aragonite (HU Min. Museum 116189), 50X, 785 nm copy.tif

Chemical structure

Aragonite.jpg

Risks

  • No significant hazards.
  • ThermoFisher: SDS

Physical and Chemical Properties

  • Orthorhombic crystal system with platy or fibrous, acicular crystals that are often twinned
  • Reacts with acids to evolve carbon dioxide.
  • Aragonite is harder and denser than calcite.
  • Fracture = subconchoidal, brittle
  • Luster = vitreous to resinous
  • Transparent to translucent
  • Streak = white
  • Fluorescence = variable
  • Birefringence = strong showing interference colors
  • Straight extinction
Composition CaCO3
Mohs Hardness 3.5 - 4.0
Density 2.93-2.95 g/ml
Refractive Index 1.530, 1.682, 1.686

Additional Images

  • Aragonite

  • Aragonite

  • Stamp seal
    MFA# 36.178

Resources and Citations

  • R. Gettens, E. West Fitzhugh, R.Feller, "Calcium Carbonate Whites", Artists Pigments, Vol. 2., A. Roy ed. Oxford University Press, Oxford, 1993.
  • Mineralogy Database: Aragonite
  • Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982
  • Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, Pigment Compendium, Elsevier Butterworth-Heinemann, Oxford, 2004 Comment: Refractive Index: alpha=1.529-1.530; beta=1.680-1.682; gamma=1.685-1.686
  • C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 131
  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
  • Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
  • The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

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