Difference between revisions of "Ammolite"
From The Gemology Project
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{{Ammolite}} | {{Ammolite}} | ||
− | Ammolite is | + | [[image:Ammolite.jpg|framed|left|Triangular Ammolite Cabochon; |
− | 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 to strengthen the ammolite.<br /> | + | Photo courtesy of Barbra Voltaire]] |
− | Color comes from interference, and it is | + | <br clear="left" /> |
+ | 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.<br /> | ||
+ | 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.<br /> | ||
+ | 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.<br /> | ||
The color play is a result of iridescence (interference). | The color play is a result of iridescence (interference). | ||
==Sources== | ==Sources== | ||
− | * ''Ammolite: Iridescent Fossilized Ammonite ..'' - Keith A. Mychaluk et all.- Gems & Gemology (Spring 2001) | + | * ''[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] |
Latest revision as of 07:54, 5 April 2008
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 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
- Ammolite: Iridescent Fossilized Ammonite .. - Keith A. Mychaluk et all.- Gems & Gemology (Spring 2001)