![]() Iridescence is the property that creates the incredible colors across the surface of ammolites. Patterns found in K Zone ammolites of the Bearpaw Formation Patterns found in Blue Zone ammolites of the Bearpaw Formation Identifying Characteristics Iridescence The geological layers in which ammonites fossilized affected the formation of these patterns. These have various descriptive names, such as: Ammolite PatternsĪmmolites can show striking patterns of healed fractures and colors. Jewelry and photo by Jessa and Mark Anderson. Sterling silver pendant with an ammolite inlay, capped with quartz. Certain hues, like crimson, violet, and gold, are very rare and in high demand. Generally, red and green are more common than blue or purple. (Sometimes, they seem to show more than that!) Low-grade gemstones will show less vibrant colors in a more limited range. These gems can show any color of the rainbow. High-grade ammolites will have either a very strong, bright, single color or a range of bright colors. A fossilized ammonite with a colorful, iridescent layer, on display at the Yokohama Dinosaur Expo, 2015. The iridescent outer layers may be 0.5-8.0 mm thick before polishing and 0.1-3.0 mm thick after polishing. These percentages make these gems extremely rare.įossilized ammonite shell is comprised primarily of aragonite (the major constituent mineral of pearl) with trace elements of aluminum, barium, chromium, copper, iron, magnesium, manganese, silicon, strontium, titanium, and vanadium. All ammolites come from that small amount of usable gem-quality material. Of those specimens, gem cutters can typically use only about 20% of the shell. Only about 5% of the ammonites found in Alberta have any suitable gem material. Although this iridescent material resembles ammolite, its mineral composition differs. Other gem-quality ammonite exists, such as lumachelle, which lapidaries cut from the fossils of C arnites floridus found in Austria. To date, this material has been found only in Alberta, Canada. The fossils of P lacenticeras meeki, P lacenticeras intercalare, and B aculites compressus can yield gem-quality ammolite. There were many species of ammonites, and their fossils have been found across the globe. Ammolite refers to the gem-quality material made from fossils of particular species of ammonites.Īmmonites were marine mollusks that became extinct around 65 million years ago. However, ammonite, strictly speaking, refers to the fossil shells of ammonites, whether gem-quality or not. You may find the terms ammolite and ammonite sometimes used interchangeably. What's the Difference Between Ammolite and Ammonite? Jewelry and photo by Korite International. In Siksika, the language of the native Blackfoot people, the stone is called aapoak, meaning "small, crawling stone." Ammolite triplet pendants and earrings. is the largest commercial supplier of this gemstone. The mining company Korite International Ltd. It was only recognized as an organic gemstone in 1981 by the Coloured Stones Commission of the World Jewellery Confederation (CIBJO).Īmmolite is also known as calcentine and by the trade name Korite. CommentsĪmmolite was first used for commercial jewelry in the 1960s. Mary River Valley, southern Alberta, southwestern Canada. ![]() Photo courtesy of and Collectors Liquidation.Īmmolite from Placenticeras fossil ammonite, found in the Bearpaw Formation, St. Gem Gradeįor more information on ammolite quality factors consult the IGS buying guide. However, most systems refer to color, brightness, iridescence, etc. The ammolite industry has yet to agree on any one grading system. This structure allows the ammolite to show the most brilliant flash while protecting it in a setting durable enough for everyday jewelry wear. On top, there’s usually a calibrated cap of optical quartz or synthetic spinel (3). Ammolite triplets are usually constructed on a dark gray wafer of natural shale (1) below a thin layer of ammolite (2). Gem cutters can also create ammolite doublets or triplets. Doublets are freeform cabs bonded to a backing. These are priced by carat weight, but the backing thickness shouldn’t exceed 1.5 mm. ![]() They’re backed by the original shale of the fossil and can range in size up to 10 carats and 6 inches across. Ammolite “naturals” are freeform cabochons with a non-coated hand finish.
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