Ammolite

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Ammolite is a gem that comes from the fossilized shell of an extinct, squid-like creature called an ammonite. Found in Canada, the iridescent shell of fossilized ammonites is available as ammonite fossils or in iridescent gems cut from the fossils under the trade name ammolite. Ammolite's iridescent play of color is what makes it so distinctive and attractive. Its iridescence occurs when the fossilized ammonite shell becomes mineralized. Unlike most gems, whose colors come from light absorption, ammolite's iridescent color is caused by interference with the light that gets trapped within stacked layers of thin platelets that make up the fossilized shell. Since the layer of ammolite is typically thin, most ammolite is made into doublets or triplets for use in jewelry. A doublet is a thin slice of shell that is typically covered by a durable material (often crystal, glass or plastic) that both protect the gem and maximize its presentation. Triplets are typically assembled by placing a thin slice of shell between two layers of more durable material that are attached with epoxy. While shades of green and red are usually seen, all spectral colors are possible.

Ammolite Polished
Ammolite Classification
Common Name Ammolite
Species Organic
Ammolite Optical Properties
Transparency Opaque
Dispersion Strength: None
Refractive Index 1.520-1.680
Tolerance:varies
Birefringence 0.155
Optic Character NA
Optic Sign NA
Polariscope Reaction Aggregate (AGG)
Fluorescence SWUV: Inert to strong yellow
LWUV: Inert to strong yellow
Pleochroism None
Ammolite Characteristic Physical Properties
Hardness 4
Specific Gravity 2.700-2.800 Typical:2.700
Toughness Varies
Inclusions Ammolite or ammonite can be iridescent with mosaic patterns. Due to the nature of the material it is often stabilized with polymers. Well preserved specimens show a nautilus or spiral like appearance. Ammolite is often made into doublets or triplets. Quartz or lab created spinel is used as a dome and the base is typically made of shale, glass or lab created spinel.
Luster Vitreous, Resinous
Fracture Granular, Uneven
Cleavage None
Ammolite Chemistry & Crystallography
Chemical Name mostly composed of aragonite or calcite
Chemical Formula fossilized, mineralized ammonite shell
Crystal System NA
Chemistry Classification Organic

Ammolite Colors

  • Multi-color Ammolite Multi-color

Alternate Names

Ammonite, Lumachelle, Calcentine

Countries of Origin

Canada; Cambodia; Unknown; Madagascar

History

Ammolite is highly iridescent and delivers light in an every-color-under-the-rainbow display. It's a gem that comes from the fossilized shell of an extinct, squid-like creature called an ammonite. The shell is a color-rich layer that is typically quite thin, so most ammolite found in jewelry is set as a doublet or triplet. Ammolite, although an ancient stone, is a relative newcomer to the jewelry scene. It emerged on the world stage as ammolite in the 1960s and was given official gemstone status by the World Jewelry Federation in 1981. There is historical evidence that suggests ammolite enjoyed popularity in amulets and talismans for centuries. One of the rarest gemstones in the world, ammolite is positioned to be a very special part of your jewelry collection.

Care

A doublet is a thin slice of shell or gemstone material that is covered by a durable layer (usually crystal, glass, or plastic) that protects the gem and may maximize its beauty. A triplet is a thin slice of shell or gemstone material that is encased in protective layers above and below.

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More About Ammolite

Today ammolite is treasured by jewelry lovers. It is also important to practitioners of the ancient Chinese art of Feng Shui, where it is known as the "Seven Color Prosperity Stone." Those who subscribe to those principles believe it bestows upon its owners health, harmony, wealth, and enlightenment. The Roman historian, Pliny the Elder, called ammonite fossils the "holiest of stones". He believed ammonite would summon dreams of prophecy.

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Tim Matthews

Author

Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.