Here is a dream of a Placenticeras intercalare from Ohio in a colourful Ammolite preservation. Ammolite is a rare and valuable organic gemstone that shows a fire like Opal.( http://en.wikipedia.org/wiki/Ammolite)
The colour spectrum of this specimen is from a deep purple-red – orange  over golden yellow down to a rich green.  Complete Ammolite Ammonites like this are only rarely found.
This piece is a fossil and a true and official gemstone as well.

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