Difference between revisions of "Fire opal"

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== Authority ==
 
== Authority ==
  
* Website address 1, Website address 1  Comment: Mineral Galleries at http://mineral.galleries.com/minerals/mineralo/opal/opal.htm  Mohs hardness=5.5-6.0
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* Website address 1  Comment: Mineral Galleries at http://mineral.galleries.com/minerals/mineralo/opal/opal.htm  Mohs hardness=5.5-6.0
  
 
* Wikipedia, the free encyclopedia, at http://www.wikipedia.com  Comment: http://en.wikipedia.org/wiki/Opal (accessed Oct. 12, 2005) specific gravity=2.1=2.3; RI=1.44 -1.46; Mohs hardness=5.5-6.6
 
* Wikipedia, the free encyclopedia, at http://www.wikipedia.com  Comment: http://en.wikipedia.org/wiki/Opal (accessed Oct. 12, 2005) specific gravity=2.1=2.3; RI=1.44 -1.46; Mohs hardness=5.5-6.6
  
* Yasukazu Suwa, Yasukazu Suwa, ''Gemstones: Quality and Value, Volume 1'', Sekai Bunka Publishing Inc., Tokyo, 1999  Comment: RI=1.450; Specific gravity=2.15
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* Yasukazu Suwa, ''Gemstones: Quality and Value, Volume 1'', Sekai Bunka Publishing Inc., Tokyo, 1999  Comment: RI=1.450; Specific gravity=2.15
  
* Michael O'Donoghue and Louise Joyner, Michael O'Donoghue and Louise Joyner, ''Identification of Gemstones'', Butterworth-Heinemann, Oxford, 2003  Comment: RI=1.45; Specific gravity=2.10
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* Michael O'Donoghue and Louise Joyner, ''Identification of Gemstones'', Butterworth-Heinemann, Oxford, 2003  Comment: RI=1.45; Specific gravity=2.10
  
 
* ''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

Revision as of 06:41, 24 July 2013

Description

A brilliant red and orange opal. Fire opals have been mined in Mexico for over 500 years. Current mines in Mexico are at Queretaro and Magdalena.

Synonyms and Related Terms

girasol; Mexican opal; water opal; jelly opal; opala de fogo (Port.); Feueropal (Deut.)

Other Properties

Mineral system=amorphous Cleavage=none Fracture=conchoidal Luster=vitreous to resinous Streak=white Fluoresce=usually white or pale green, some samples phosphoresce

Composition SiO2·nH2O
Mohs Hardness 5.5-6.0
Density 2.1-2.3
Refractive Index 1.44-1.46

Hazards and Safety

Higly hydrated; may be subject to dehydration and surface cracking.

Additional Information

Mineral Galleries: Website

Authority

  • Yasukazu Suwa, Gemstones: Quality and Value, Volume 1, Sekai Bunka Publishing Inc., Tokyo, 1999 Comment: RI=1.450; Specific gravity=2.15
  • Michael O'Donoghue and Louise Joyner, Identification of Gemstones, Butterworth-Heinemann, Oxford, 2003 Comment: RI=1.45; Specific gravity=2.10
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
  • The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

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