Ammonite the Fossil - now extinct, the ammonite mollusc was a shelled cephalopod, usually appearing in a coiled, spiral shape. The extinction of ammonites coincided with the extinction of dinosaurs. Ammonites inhabited the world’s oceans and now appear as fossils in marine rocks. Because of their rapid evolution and wide distribution, ammonite fossils provide a useful tool for indexing and dating rocks. It is said that the original discus used by the ancient Greeks in their Olympics was in fact a fossilised ammonite. In India, ammonite fossils are identified with the god Vishnu and are used in various ceremonies. They are mostly collected in Nepal, from the bed of the River Gandaki where it cuts through Jurassic sediments. These fossils are known as "shaligram shila". The word ammonite is derived from Ammon, an Egyptian god who took the form of a ram. Ammonites are similar in appearance to a ram's horn.
Ammolite the Gemstone - is an opal-like organic gemstone found primarily along the eastern slopes of the Rocky Mountains of North America. It is made of the fossilized shells of ammonites, which in turn are composed primarily of aragonite, the same mineral contained in nacre, with a microstructure inherited from the shell. It is one of few biogenic gemstones; others include amber and pearl. In 1981, ammolite was given official gemstone status by the World Jewellery Confederation, the same year commercial mining of ammolite began.
Ammonites can be distinguished their shape which looks like a coil with a wide mouth. The chambered part of the ammonite shell is called a phragmocone. It contains a series of progressively larger chambers, called camerae that are divided by thin walls called septa. Only the last and largest chamber, the body chamber, was occupied by the living animal at any given moment. As it grew, it added newer and larger chambers to the open end of the coil.
Ammolite is a rare, gem-quality, iridescent material. It's cut from the fossilized shells of extinct ammonites and found only in the Bearpaw Formation in Alberta, Canada. With a wide range of dazzling colors and patterns, this organic gemstone is highly desired for freeform natural cabochons and assembled jewelry pieces.
Ammolite “naturals” are freeform cabochons with a non-coated hand finish. They're backed by the original shale of the fossil.
Doublets are freeform cabochons bonded to a backing.
Ammolite triplets are usually constructed on a dark gray wafer of natural shale below a thin layer of ammolite. On top, there's usually a calibrated cap of optical quartz or synthetic spinel. This structure allows the ammolite to show the most brilliant flash while protecting it in a setting durable enough for everyday jewelry wear.