Wikipedia:Today's featured article/March 5, 2005

Ammolite is a very rare and valuable opal-like organic gemstone found only along the eastern slopes of the Rocky Mountains of the United States and Canada. It is made of the fossilized shells of ammonites, which in turn are composed primarily of aragonite, the same organic mineral that makes up nacreous pearls. It is one of the three organic gemstones (excluding those used primarily as ornamental materials rather than discrete stones), the other two being amber and pearl. In 1981, ammolite was given official gemstone status by the CIBJO, the same year commercial mining of ammolite began. In 2004 it was designated the official gemstone of the Province of Alberta. Ammolite is also known as aapoak (Kainah for "small, crawling stone"), gem ammonite, calcentine, and korite. The latter is a trade name given to the gemstone by the Alberta-based mining company Korite International, the first and largest commercial producer of ammolite. (more...)

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