Difference between revisions of "Ammolite"

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(Sources)
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==Sources==
 
==Sources==
  
* ''Ammolite: Iridescent Fossilized Ammonite ..'' - Keith A. Mychaluk et all.- Gems & Gemology (Spring 2001)
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* ''[http://www.gia.edu/gemsandgemology/18578/1453/403/back_issue_article_detail.cfm| Ammolite: Iridescent Fossilized Ammonite ..]]'' - Keith A. Mychaluk et all.- Gems & Gemology (Spring 2001)
  
 
==External links==
 
==External links==
  
 
* [http://www.gemsociety.org/info/gems/ammolite.htm Gem Society - Ammolite]
 
* [http://www.gemsociety.org/info/gems/ammolite.htm Gem Society - Ammolite]

Revision as of 07:09, 19 January 2007

Ammolite
Chemical composition CaC03 with trace elements
Crystal system Orthorhombic
Habit Fractured and non-fractured flat layers
Fracture Parting along layers
Hardness 3.5
Refractive index 1.525 - 1.670
Birefringence 0.135 - 0.145
Specific gravity 2.60 - 2.85
Lustre Vitreous to resinous

Ammolite.jpg
Ammolite is the iridescent gem variety of a unique fossil ammonite, currently excavated only in southern Alberta, Canada. Ammonites are an extinct marine animal that first appeared 400 million years ago and became extinct at the end of the Cretaceous Period, 65 million years ago.
Natural ammolite has a hardness of 3.5, but is most often sold as a doublet or triplet in order to protect the gem material. Natural stones are often impregnated with an epoxy as a treatment to strengthen the ammolite.
Color comes from interference of light, and it is dependent on the thickness of the layers of aragonite. From thickest to thinnest: red, green, blue, and purple.
The color play is a result of iridescence (interference).

Sources

External links