Difference between revisions of "Witherite"

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== Description ==
 
== Description ==
  
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A naturally occurring mineral composed of [http://cameo.mfa.org/materials/fullrecord.asp?name=barium%20carbonate barium carbonate]. Witherite was named for william Withering an 18th century English naturalist.  It is usually found in hydrothermal veins associated with [http://cameo.mfa.org/materials/fullrecord.asp?name=barite barite]. Witherite is mined in Germany, England (Hexham, Northumberland, Cumberland, Durham), Scotland, Canada (Ontario) and the U.S. (Illinois, California, Arizona). Witherite is used in case-hardening [http://cameo.mfa.org/materials/fullrecord.asp?name=steel steel] and in refining [http://cameo.mfa.org/materials/fullrecord.asp?name=sugar sugar]. It is also used as a pigment in the manufacture of [http://cameo.mfa.org/materials/fullrecord.asp?name=paint paints], [http://cameo.mfa.org/materials/fullrecord.asp?name=glaze glazes], and synthetic [http://cameo.mfa.org/materials/fullrecord.asp?name=marble marble].
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A naturally occurring mineral composed of [[barium%20carbonate|barium carbonate]]. Witherite was named for william Withering an 18th century English naturalist.  It is usually found in hydrothermal veins associated with [[barite|barite]]. Witherite is mined in Germany, England (Hexham, Northumberland, Cumberland, Durham), Scotland, Canada (Ontario) and the U.S. (Illinois, California, Arizona). Witherite is used in case-hardening [[steel|steel]] and in refining [[sugar|sugar]]. It is also used as a pigment in the manufacture of [[paint|paints]], [[glaze|glazes]], and synthetic [[marble|marble]].
  
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[[[SliderGallery rightalign|Witherite, PMA.TIF~FTIR (PMA)|witheriteRS.jpg~Raman]]]
 
== Synonyms and Related Terms ==
 
== Synonyms and Related Terms ==
  
 
barium carbonate; Pigment White 10; CI 77099
 
barium carbonate; Pigment White 10; CI 77099
  
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[[[SliderGallery rightalign|witheriteRS.jpg~Raman]]]
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== Risks ==
  
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== Other Properties ==
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* Toxic by ingestion. 
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* Skin contact may cause irritation.
  
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Soluble in acids. Insoluble in water. 
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==Physical and Chemical Properties==
  
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Orthorhombic crystals, usually short and prismatic.  Cleavage is good in one direction.   
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* Soluble in acids. Insoluble in water. 
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* Orthorhombic crystals, usually short and prismatic.   
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Fracture = subconchoidal.  Luster = veitreous to resinous.  Streak = white.  
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* Cleavage is good in one direction.   
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* Fracture = subconchoidal.   
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Flat tablets that are colorless under plane-polarized light; high brefringence with complete extinction; interference colors are often seen.   
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* Luster = veitreous to resinous.   
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* Streak = white.  
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Fluoresces a light blue color in both long- and short-wave UV and is phosphorescent under short-wave UV light
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* Flat tablets that are colorless under plane-polarized light; high brefringence with complete extinction; interference colors are often seen.   
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* Fluoresces a light blue color in both long- and short-wave UV and is phosphorescent under short-wave UV light
  
 
{| class="wikitable"
 
{| class="wikitable"
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|-
 
|-
 
! scope="row"| Density
 
! scope="row"| Density
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| 4.3
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| 4.3 g/ml
 
|-
 
|-
 
! scope="row"| Refractive Index
 
! scope="row"| Refractive Index
 
| 1.529-1.677
 
| 1.529-1.677
 
|}
 
|}
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== Hazards and Safety ==
 
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Toxic by ingestion.  Skin contact may cause irritation.
 
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== Additional Information ==
 
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Mineralogy Database: [http://www.webmineral.com/data/Witherite.shtml Witherite]
 
  
 
== Comparisons ==
 
== Comparisons ==
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[[media:download_file_538.pdf|Characteristics of Common White Pigments]]
 
[[media:download_file_538.pdf|Characteristics of Common White Pigments]]
  
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==Resources and Citations==
  
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* Mineralogy Database: [http://www.webmineral.com/data/Witherite.shtml Witherite]
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== Authority ==
 
  
 
* Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, ''Pigment Compendium'', Elsevier Butterworth-Heinemann, Oxford, 2004  Comment: Vol. 2, page 267. Refractive index: alpha=1.529, beta=1.676, gamma=1.677.  Microscopically similar to aragontie
 
* Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, ''Pigment Compendium'', Elsevier Butterworth-Heinemann, Oxford, 2004  Comment: Vol. 2, page 267. Refractive index: alpha=1.529, beta=1.676, gamma=1.677.  Microscopically similar to aragontie
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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
 
* 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/Witherite (Accessed Sept. 20, 2005)
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* Wikipedia: http://en.wikipedia.org/wiki/Witherite (Accessed Sept. 20, 2005)
  
 
* Michael McCann, ''Artist Beware'', Watson-Guptill Publications, New York City, 1979
 
* Michael McCann, ''Artist Beware'', Watson-Guptill Publications, New York City, 1979

Latest revision as of 10:41, 27 June 2022

Witherite

Description

A naturally occurring mineral composed of Barium carbonate. Witherite was named for william Withering an 18th century English naturalist. It is usually found in hydrothermal veins associated with Barite. Witherite is mined in Germany, England (Hexham, Northumberland, Cumberland, Durham), Scotland, Canada (Ontario) and the U.S. (Illinois, California, Arizona). Witherite is used in case-hardening Steel and in refining Sugar. It is also used as a pigment in the manufacture of paints, glazes, and synthetic Marble.

FTIR (PMA)

Witherite, PMA.TIF

Raman

WitheriteRS.jpg

Synonyms and Related Terms

barium carbonate; Pigment White 10; CI 77099

Risks

  • Toxic by ingestion.
  • Skin contact may cause irritation.

Physical and Chemical Properties

  • Soluble in acids. Insoluble in water.
  • Orthorhombic crystals, usually short and prismatic.
  • Cleavage is good in one direction.
  • Fracture = subconchoidal.
  • Luster = veitreous to resinous.
  • Streak = white.
  • Flat tablets that are colorless under plane-polarized light; high brefringence with complete extinction; interference colors are often seen.
  • Fluoresces a light blue color in both long- and short-wave UV and is phosphorescent under short-wave UV light
Mohs Hardness 3.0 - 3.5
Density 4.3 g/ml
Refractive Index 1.529-1.677

Comparisons

Characteristics of Common White Pigments

Resources and Citations

  • Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, Pigment Compendium, Elsevier Butterworth-Heinemann, Oxford, 2004 Comment: Vol. 2, page 267. Refractive index: alpha=1.529, beta=1.676, gamma=1.677. Microscopically similar to aragontie
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 84
  • C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
  • 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

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