Difference between revisions of "Aragonite"
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== Description == | == Description == | ||
| − | A crystalline form of [http://cameo.mfa.org/materials/fullrecord.asp?name=calcium | + | A crystalline form of [http://cameo.mfa.org/materials/fullrecord.asp?name=calcium%20carbonate calcium carbonate] that occurs in [http://cameo.mfa.org/materials/fullrecord.asp?name=coral coral], [http://cameo.mfa.org/materials/fullrecord.asp?name=seashell shells], [http://cameo.mfa.org/materials/fullrecord.asp?name=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 [http://cameo.mfa.org/materials/fullrecord.asp?name=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. |
[[File:36.178-20-3.jpg|thumb|]] | [[File:36.178-20-3.jpg|thumb|]] | ||
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== Additional Information == | == Additional Information == | ||
| − | R. Gettens, E. West Fitzhugh, R.Feller, "Calcium Carbonate Whites", ''Artists Pigments'', Vol. 2., A. Roy ed. Oxford University Press, Oxford, 1993. | + | ° R. Gettens, E. West Fitzhugh, R.Feller, "Calcium Carbonate Whites", ''Artists Pigments'', Vol. 2., A. Roy ed. Oxford University Press, Oxford, 1993. ° Mineralogy Database: [http://www.webmineral.com/data/Aragonite.shtml Aragonite] |
== Additional Images == | == Additional Images == | ||
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== Authority == | == Authority == | ||
| − | * | + | * 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 |
| − | * ''Encyclopedia Britannica'', http://www.britannica.com Comment: aragonite" | + | * ''Encyclopedia Britannica'', http://www.britannica.com Comment: aragonite" Encyclopædia Britannica [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 |
* Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: http://en.wikipedia.org/wiki/Aragonite (Accessed Aug. 30 2005) | * Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: 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 |
| − | * | + | * 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 | * ''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 | * ''The American Heritage Dictionary'' or ''Encarta'', via Microsoft Bookshelf 98, Microsoft Corp., 1998 | ||
Revision as of 07:39, 24 July 2013
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.
Synonyms and Related Terms
calcium carbonate; nacre; shell white; coral; Aragonit (Deut., Pol.); aragonita (Esp.); aragonito (Esp.); aragonite (Fr., Port.); aragoniet (Ned.)
Other Properties
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.
Luster = vitreous to resinous. Transparent to translucent. Fracture = subconchoidal. Streak = white
Strongly birefringent showing interference colors. Straight extinction
| Composition | CaCO3 |
|---|---|
| CAS | 471-34-1 |
| Mohs Hardness | 3.5 - 4.0 |
| Density | 2.93-2.95 |
| Molecular Weight | mol. wt. = 100.09 |
| Refractive Index | 1.530, 1.682, 1.686 |
Hazards and Safety
No significant hazards.
Mallinckrodt Baker: MSDS
Additional Information
° 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
Additional Images
Aragonite
Aragonite
Authority
- 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
- Encyclopedia Britannica, http://www.britannica.com Comment: aragonite" Encyclopædia Britannica [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
- Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: 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
- 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