Difference between revisions of "Chrysoberyl"

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[[File:Necklace Chrysoberyl SC237669.jpg|thumb|Revival necklace<br>MFA# 2015.3184]]
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== Description ==
 
[[File:pc21249chrysoberyl.jpg|thumb|Chrysoberyl]]
 
[[File:pc21249chrysoberyl.jpg|thumb|Chrysoberyl]]
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== Description ==
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A hard green to yellow mineral composed of beryllium aluminate. Chrysoberyl occurs in granitic rocks, pegmatites, and mica schists. Some transparent varieties of chrysoberyl have been used as [[gemstone|gemstones]]. In the 18th century, a large deposit of clear, yellowish-green chrysoberyls was found in Brazil and the stones were popularly used for Portuguese and Spanish jewelry. [[Cat's eye]] chrysoberyls are cut as [[cabochon|cabochons]] and polished. The [[alexandrite]] variety of chrysoberyl appears red in artificial light and green in daylight. Chrysoberyls are found in the Ural Mountains (alexandrite), Czech Republic, Sri Lanka, Rhodesia, Brazil, Malagasy Republic and the United States (New York, Colorado).
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A hard green to yellow mineral composed of beryllium aluminate. Chrysoberyl occurs in granitic rocks, pegmatites, and mica schists. Some transparent varieties of chrysoberyl have been used as [http://cameo.mfa.org/materials/fullrecord.asp?name=gemstone gemstones]. In the 18th century, a large deposit of clear, yellowish-green chrysoberyls was found in Brazil and the stones were popularly used for Portuguese and Spanish jewelry. [http://cameo.mfa.org/materials/fullrecord.asp?name=Cat%27s%20eye Cat's eye] chrysoberyls are cut as [http://cameo.mfa.org/materials/fullrecord.asp?name=cabochon cabochons] and polished. The [http://cameo.mfa.org/materials/fullrecord.asp?name=alexandrite alexandrite] variety of chrysoberyl appears red in artificial light and green in daylight. Chrysoberyls are found in the Ural Mountains (alexandrite), Czech Republic, Sri Lanka, Rhodesia, Brazil, Malagasy Republic and the United States (New York, Colorado).
 
  
 
== Synonyms and Related Terms ==
 
== Synonyms and Related Terms ==
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cat's eye; cymophane; golden beryl; alexandrite; oriental chrysolite; crisoberilo (Esp., Port.); chryzoberyl (Pol.); Chrysoberyll (Deut.); chrysoberyl (Ned.)
 
cat's eye; cymophane; golden beryl; alexandrite; oriental chrysolite; crisoberilo (Esp., Port.); chryzoberyl (Pol.); Chrysoberyll (Deut.); chrysoberyl (Ned.)
  
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[[[SliderGallery rightalign|chrysoberylRS.jpg~Raman]]]
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[[File:Chrysoberyl Raman RRUFF R0110103.png|thumb|Raman spectrum of Chrysoberyl from [https://rruff.info/alexandrite/display=default/R110103 RRUFF]]]
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==Physical and Chemical Properties==
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== Other Properties ==
 
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Orthorhombic crystal system.  Good cleavage in one direction.   
 
  
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Fracture = uneven to conchoidal. Luster = vitreous. Streak = colorless to white. Alexandrite is trongly pleochroic.
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* Orthorhombic crystal system with tabular or short prismatic crystals 
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* Good cleavage in one direction   
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* Fracture = uneven to conchoidal  
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* Luster = vitreous   
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* Streak = colorless to white
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* Fluorescence = generally inert; yellow to green stone may show weak yellow under SW; 'mint' chrysoberyl shows strong red in LW
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* Pleochroism = generally weak to moderate (red, yellow, green); Alexandrite is strongly pleochroic (green, red)
  
 
{| class="wikitable"
 
{| class="wikitable"
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|-
 
|-
 
! scope="row"| Density
 
! scope="row"| Density
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| 3.5-3.8
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| 3.5-3.8 g/ml
 
|-
 
|-
 
! scope="row"| Refractive Index
 
! scope="row"| Refractive Index
 
| 1.745-1.754
 
| 1.745-1.754
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|-
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! scope="row"| Birefringence
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| 0.008 - 0.010
 
|}
 
|}
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== Additional Information ==
 
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Mineralogy Database: [http://www.webmineral.com/data/Chrysoberyl.shtml Chrysoberyl]
 
  
 
== Comparisons ==
 
== Comparisons ==
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[[media:download_file_403.pdf|Properties of Gemstones]]
 
[[media:download_file_403.pdf|Properties of Gemstones]]
  
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==Resources and Citations==
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* Mineralogy Database: [http://www.webmineral.com/data/Chrysoberyl.shtml Chrysoberyl]
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== Authority ==
 
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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
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* Gem Identification Lab Manual, Gemological Institute of America, 2016.
 
* R.F.Symmes, T.T.Harding, Paul Taylor, ''Rocks, Fossils and Gems'', DK Publishing, Inc., New York City, 1997
 
* R.F.Symmes, T.T.Harding, Paul Taylor, ''Rocks, Fossils and Gems'', DK Publishing, Inc., New York City, 1997
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* ''Encyclopedia Britannica'', http://www.britannica.com  Comment: "chrysoberyl." Accessed 7 Apr. 2005 .
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* ''Encyclopedia Britannica'', http://www.britannica.com  Comment: "chrysoberyl." Encyclopædia Britannica. 2005. Encyclopædia Britannica Premium Service  7 Apr. 2005 .
 
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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: [https://en.wikipedia.org/wiki/Chrysoberyl#Alexandrite Chrysoberyl] (Accessed Sept. 2, 2005 and Dec 2022)
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* Wikipedia, the free encyclopedia, at http://www.wikipedia.com  Comment: http://en.wikipedia.org/wiki/Chrysoberyl (Accessed Sept. 2, 2005)
 
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* G.S.Brady, ''Materials Handbook'', McGraw-Hill Book Co., New York, 1971  Comment: p. 101
 
* G.S.Brady, ''Materials Handbook'', McGraw-Hill Book Co., New York, 1971  Comment: p. 101
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* ''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
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* Random House, ''Webster's Encyclopedic Unabridged Dictionary of the English Language'', Grammercy Book, New York, 1997
 
* Random House, ''Webster's Encyclopedic Unabridged Dictionary of the English Language'', Grammercy Book, New York, 1997
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* ''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
  

Latest revision as of 12:59, 23 December 2022

Revival necklace
MFA# 2015.3184

Description

Chrysoberyl

A hard green to yellow mineral composed of beryllium aluminate. Chrysoberyl occurs in granitic rocks, pegmatites, and mica schists. Some transparent varieties of chrysoberyl have been used as gemstones. In the 18th century, a large deposit of clear, yellowish-green chrysoberyls was found in Brazil and the stones were popularly used for Portuguese and Spanish jewelry. Cat's eye chrysoberyls are cut as cabochons and polished. The Alexandrite variety of chrysoberyl appears red in artificial light and green in daylight. Chrysoberyls are found in the Ural Mountains (alexandrite), Czech Republic, Sri Lanka, Rhodesia, Brazil, Malagasy Republic and the United States (New York, Colorado).

Synonyms and Related Terms

cat's eye; cymophane; golden beryl; alexandrite; oriental chrysolite; crisoberilo (Esp., Port.); chryzoberyl (Pol.); Chrysoberyll (Deut.); chrysoberyl (Ned.)

Raman spectrum of Chrysoberyl from RRUFF

Physical and Chemical Properties

  • Orthorhombic crystal system with tabular or short prismatic crystals
  • Good cleavage in one direction
  • Fracture = uneven to conchoidal
  • Luster = vitreous
  • Streak = colorless to white
  • Fluorescence = generally inert; yellow to green stone may show weak yellow under SW; 'mint' chrysoberyl shows strong red in LW
  • Pleochroism = generally weak to moderate (red, yellow, green); Alexandrite is strongly pleochroic (green, red)
Composition BeAl2O4
Mohs Hardness 8.5
Density 3.5-3.8 g/ml
Refractive Index 1.745-1.754
Birefringence 0.008 - 0.010

Comparisons

Properties of Gemstones

Resources and Citations

  • Mineralogy Database: Chrysoberyl
  • Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982
  • Gem Identification Lab Manual, Gemological Institute of America, 2016.
  • R.F.Symmes, T.T.Harding, Paul Taylor, Rocks, Fossils and Gems, DK Publishing, Inc., New York City, 1997
  • Encyclopedia Britannica, http://www.britannica.com Comment: "chrysoberyl." Accessed 7 Apr. 2005 .
  • C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
  • Wikipedia: Chrysoberyl (Accessed Sept. 2, 2005 and Dec 2022)
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 101
  • 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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