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Ammolite-a rare mineralized fossil shell- is also known as Korite are beleived to have formed over 70 million years ago. The most notable source is Alberta, Canada. The shell material is classified (class/genus/species) as Cephalopoda/Ammonoidea/placenticeras meeki. Ammononite comes in highly iridescent colors including white and shades of red, green, blue, gold, orange and purple.
The shell varies in size and can be as small in diameter as a dime to larger ones bigger than a dinner plate. The iridescent layer is made of aragonite and maybe as thick as 6mm. However, this thickness is usually too thin to make into jewelry and is reinforced by fabricating it into "triplets" which provides a protective quartz or synthetic colorless spinel top and black onyx backing for more durabilty.
The chemical formula is CaCO3. Hardness of 4. Luster ranges from vitreous to resinous. It has several clevage directions and is brittle. A density of 2.80 ( pure aragonite=2.90). Birefrigence of 0.150. Crystal habbit is Orthorhombic( aragonite). Sometimes called calcetine. |
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