Difference between revisions of "Gypsum"

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== Description ==
 
== Description ==
  
A soft, transparent, easily cleaved mineral composed of [http://cameo.mfa.org/materials/fullrecord.asp?name=calcium sulfate, dihydrate hydrated calcium sulfate]. Gypsum is found as twinned monoclinic crystals, called [http://cameo.mfa.org/materials/fullrecord.asp?name=selenite selenite], or silky fibrous crystals, called [http://cameo.mfa.org/materials/fullrecord.asp?name=satin spar satin spar]. Massive blocks of fine-grain white, translucent gypsum are called [http://cameo.mfa.org/materials/fullrecord.asp?name=alabaster alabaster] and have been used since ancient times for carved ornamental objects and statuary. Gypsum is a commonly found mineral associated with sedimentary rock and deposits from seas, lakes, and volcanic springs ([http://cameo.mfa.org/materials/fullrecord.asp?name=gypcrete gypcrete]). For a long time, gypsum quarries in the Montmartre district of Paris supplied the starting material for the burnt gypsum that was, and still is, called [http://cameo.mfa.org/materials/fullrecord.asp?name=plaster of Paris plaster of Paris]. Raw gypsum is used for carvings ([http://cameo.mfa.org/materials/fullrecord.asp?name=alabaster alabaster]), for wallboards ([http://cameo.mfa.org/materials/fullrecord.asp?name=Sheetrock Sheetrock]), as a filler in paper ([http://cameo.mfa.org/materials/fullrecord.asp?name=crown filler crown filler]), as a paint pigment ([http://cameo.mfa.org/materials/fullrecord.asp?name=terra alba terra alba]) and as an ingredient in [http://cameo.mfa.org/materials/fullrecord.asp?name=portland cement portland cement]. Finely ground gypsum was mixed with rabbit skin glue and used as [http://cameo.mfa.org/materials/fullrecord.asp?name=gesso gesso].
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A soft, transparent, easily cleaved mineral composed of [http://cameo.mfa.org/materials/fullrecord.asp?name=calcium%20sulfate%2C%20dihydrate hydrated calcium sulfate]. Gypsum is found as twinned monoclinic crystals, called [http://cameo.mfa.org/materials/fullrecord.asp?name=selenite selenite], or silky fibrous crystals, called [http://cameo.mfa.org/materials/fullrecord.asp?name=satin%20spar satin spar]. Massive blocks of fine-grain white, translucent gypsum are called [http://cameo.mfa.org/materials/fullrecord.asp?name=alabaster alabaster] and have been used since ancient times for carved ornamental objects and statuary. Gypsum is a commonly found mineral associated with sedimentary rock and deposits from seas, lakes, and volcanic springs ([http://cameo.mfa.org/materials/fullrecord.asp?name=gypcrete gypcrete]). For a long time, gypsum quarries in the Montmartre district of Paris supplied the starting material for the burnt gypsum that was, and still is, called [http://cameo.mfa.org/materials/fullrecord.asp?name=plaster%20of%20Paris plaster of Paris]. Raw gypsum is used for carvings ([http://cameo.mfa.org/materials/fullrecord.asp?name=alabaster alabaster]), for wallboards ([http://cameo.mfa.org/materials/fullrecord.asp?name=Sheetrock%C2%AE Sheetrock®]), as a filler in paper ([http://cameo.mfa.org/materials/fullrecord.asp?name=crown%20filler crown filler]), as a paint pigment ([http://cameo.mfa.org/materials/fullrecord.asp?name=terra%20alba terra alba]) and as an ingredient in [http://cameo.mfa.org/materials/fullrecord.asp?name=portland%20cement portland cement]. Finely ground gypsum was mixed with rabbit skin glue and used as [http://cameo.mfa.org/materials/fullrecord.asp?name=gesso gesso].
  
 
[[File:35.731-SC80319.jpg|thumb|]]
 
[[File:35.731-SC80319.jpg|thumb|]]
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native calcium sulfate; alabaster; selenite; terra alba; satinite; mineral white; satin spar; light spar; sulfate of lime; puritan filler; crown filler; Pigment White 25; Gips (Deut.); gips (Ned., Pol.); yeso (Esp.); gypse (Fr.); gesso (It., Port.)
 
native calcium sulfate; alabaster; selenite; terra alba; satinite; mineral white; satin spar; light spar; sulfate of lime; puritan filler; crown filler; Pigment White 25; Gips (Deut.); gips (Ned., Pol.); yeso (Esp.); gypse (Fr.); gesso (It., Port.)
  
[[[SliderGallery rightalign|GypsumUCL.jpg~Raman|Gypsumitaly1.jpg~Raman|PIGCASO4.jpg~XRD]]]
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[[[SliderGallery rightalign|GypsumUCL.jpg~Raman|Gypsumitaly1.jpg~Raman|Gypsum, calcium sulfate dihydrate.jpg~FTIR|PIGCASO4.jpg~XRD]]]
  
 
== Other Properties ==
 
== Other Properties ==
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File:gypsumlarge.jpg|Gypsum
 
File:gypsumlarge.jpg|Gypsum
 
File:Gypsum C100x.jpg|Gypsum
 
File:Gypsum C100x.jpg|Gypsum
File:Gypsum, calcium sulfate dihydrate.jpg|Infrared spectrum of gypsum
 
 
</gallery>
 
</gallery>
  
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== Authority ==
 
== Authority ==
  
* Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, ''Pigment Compendium'', Elsevier Butterworth-Heinemann, Oxford, 2004  Comment: Refractive Index: alpha=1.519-1.521; beta=1.522-1.523; gamma=1.529-1.530
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* Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, ''Pigment Compendium'', Elsevier Butterworth-Heinemann, Oxford, 2004  Comment: Refractive Index: alpha=1.519-1.521; beta=1.522-1.523; gamma=1.529-1.530
  
 
* ''Encyclopedia Britannica'', http://www.britannica.com  Comment: "gypsum"  [Accessed December 4, 2001 (B/W photo)
 
* ''Encyclopedia Britannica'', http://www.britannica.com  Comment: "gypsum"  [Accessed December 4, 2001 (B/W photo)
  
* C.W.Chesterman, K.E.Lowe, 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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* 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/Gypsum (Accessed Nov. 2, 2005)
 
* Wikipedia, the free encyclopedia, at http://www.wikipedia.com  Comment: http://en.wikipedia.org/wiki/Gypsum (Accessed Nov. 2, 2005)
  
* R. J. Gettens, G.L. Stout, R. J. Gettens, G.L. Stout, ''Painting Materials, A Short Encyclopaedia'', Dover Publications, New York, 1966  Comment: density = 2.36 and ref.index =.1.520 ;1.530; 1.523
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* R. J. Gettens, G.L. Stout, ''Painting Materials, A Short Encyclopaedia'', Dover Publications, New York, 1966  Comment: density = 2.36 and ref.index =.1.520 ;1.530; 1.523
  
* G.S.Brady, G.S.Brady, ''Materials Handbook'', McGraw-Hill Book Co., New York, 1971  Comment: p. 385
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* G.S.Brady, ''Materials Handbook'', McGraw-Hill Book Co., New York, 1971  Comment: p. 385
  
 
* ''Dictionary of Building Preservation'', Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996
 
* ''Dictionary of Building Preservation'', Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996
  
* Michael McCann, Michael McCann, ''Artist Beware'', Watson-Guptill Publications, New York City, 1979
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* Michael McCann, ''Artist Beware'', Watson-Guptill Publications, New York City, 1979
  
* Matt Roberts, Don Etherington, Matt Roberts, Don Etherington, ''Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology'', U.S. Government Printing Office, Washington DC, 1982
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* Matt Roberts, Don Etherington, ''Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology'', U.S. Government Printing Office, Washington DC, 1982
  
* Sue Fuller, Sue Fuller, ''Rocks and Minerals'', DK Publishing, Inc., New York City, 1995
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* Sue Fuller, ''Rocks and Minerals'', DK Publishing, Inc., New York City, 1995
  
* Jack Odgen, Jack Odgen, ''Jewellery of the Ancient World'', Rizzoli International Publications Inc., New York City, 1982
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* Jack Odgen, ''Jewellery of the Ancient World'', Rizzoli International Publications Inc., New York City, 1982
  
 
* ''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, Random House, ''Webster's Encyclopedic Unabridged Dictionary of the English Language'', Grammercy Book, New York, 1997
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* 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
  
* Thomas B. Brill, Thomas B. Brill, ''Light Its Interaction with Art and Antiquities'', Plenum Press, New York City, 1980  Comment: ref. index = 1.21; 1.52; 1.53
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* Thomas B. Brill, ''Light Its Interaction with Art and Antiquities'', Plenum Press, New York City, 1980  Comment: ref. index = 1.21; 1.52; 1.53
  
* Susan E. Schur, Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, ''Technology and Conservation'', Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985
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* Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, ''Technology and Conservation'', Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985
  
 
* ''The Merck Index'', Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983  Comment: entry 1753
 
* ''The Merck Index'', Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983  Comment: entry 1753

Revision as of 07:49, 24 July 2013

1995.739-E12832CR-d1.jpg

Description

A soft, transparent, easily cleaved mineral composed of hydrated calcium sulfate. Gypsum is found as twinned monoclinic crystals, called selenite, or silky fibrous crystals, called satin spar. Massive blocks of fine-grain white, translucent gypsum are called alabaster and have been used since ancient times for carved ornamental objects and statuary. Gypsum is a commonly found mineral associated with sedimentary rock and deposits from seas, lakes, and volcanic springs (gypcrete). For a long time, gypsum quarries in the Montmartre district of Paris supplied the starting material for the burnt gypsum that was, and still is, called plaster of Paris. Raw gypsum is used for carvings (alabaster), for wallboards (Sheetrock®), as a filler in paper (crown filler), as a paint pigment (terra alba) and as an ingredient in portland cement. Finely ground gypsum was mixed with rabbit skin glue and used as gesso.

35.731-SC80319.jpg

Synonyms and Related Terms

native calcium sulfate; alabaster; selenite; terra alba; satinite; mineral white; satin spar; light spar; sulfate of lime; puritan filler; crown filler; Pigment White 25; Gips (Deut.); gips (Ned., Pol.); yeso (Esp.); gypse (Fr.); gesso (It., Port.)

Raman

GypsumUCL.jpg

Raman

Gypsumitaly1.jpg

FTIR

Gypsum, calcium sulfate dihydrate.jpg

XRD

PIGCASO4.jpg


Other Properties

Soluble in water. Slightly soluble in glycerol and weak acids. Precipitates as needle-like crystals. Insoluble in most organic solvents. Gypsum fluoresces purple.

Low birefringence. Perfect cleavage in one direction and good cleavage in two directions.

Luster = vitreous, silky or pearly. Streak = white. Fracture = conchoidal to splintery. Euhedral shaped crystals contain numerous inclusions.

Composition CaSO4-2H2O
CAS 1010-14-4
Mohs Hardness 1.5 - 2.0
Melting Point 100-150
Density 2.32-2.36
Molecular Weight mol. wt. = 172.2
Refractive Index 1.520; 1.523; 1.530

Hazards and Safety

Inhalation and contact may cause slight allergies.

LINK: International Chemical Safety Card

Additional Information

Mineralogy Database: Gypsum

Comparisons

Characteristics of Common White Pigments


Additional Images


Authority

  • Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, Pigment Compendium, Elsevier Butterworth-Heinemann, Oxford, 2004 Comment: Refractive Index: alpha=1.519-1.521; beta=1.522-1.523; gamma=1.529-1.530
  • C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
  • R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966 Comment: density = 2.36 and ref.index =.1.520 ;1.530; 1.523
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 385
  • Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996
  • Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
  • Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982
  • Sue Fuller, Rocks and Minerals, DK Publishing, Inc., New York City, 1995
  • Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982
  • 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
  • Thomas B. Brill, Light Its Interaction with Art and Antiquities, Plenum Press, New York City, 1980 Comment: ref. index = 1.21; 1.52; 1.53
  • Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 1753
  • CRC Handbook of Chemistry and Physics, Robert Weast (ed.), CRC Press, Boca Raton, Florida, v. 61, 1980 Comment: density=2.31-2.33

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