Encyclopedia » Ammolite

Ammolite

Artist's conception of the ammonite.Ammolite is a biogenic gemstone. It forms as thin sheets on the shells of extinct ammonites

Ammonite is a sea creature that became extinct 65.5 million years ago.

Although the outward appearance of the ammonite resembles that of the nautilus, its genetic composition is more closely related to the squid, octupus, or cuttlefish.

The gemstone consists primarily of calcium carbonate, with traces of other minerals such as silica or calcite. The shell of the ammonite is a form of aragonite.

The brilliant iridescence of the gemstone is highly prized, as it can reflect light in all the colours of the rainbow. The effect is achieved through millions of years of geological change in while the shell of the ancient mollusk is fossilized.

Ammolite is valued by grade — the more colours it reflects, the higher the grade. Red and green are the most common colours, with blue and purple following. Three-colour combinations such as red, violet and gold are most rare and highly demanded.

The thickness of the ammolite layer on the shell and the absence of cracks on its surface are also factors when considering its value.

Ammonite fossils are found throughout the world, but the most brilliantly coloured are exclusive to southern Alberta, Canada. A prominent mine is the Korite mine near Lethbridge, from which especially large and intact specimens are discovered. Every ammonite specimen exported from Canada requires a permit from provincial regulators and the federal Department of Canadian Heritage (Boswell, 50).

Considered one of the rarest and most valuable organic gemstones in the world, it is popular for jewellery but, because of its poor hardness (4.5 – 5.5 on the Moh’s scale), it may be difficult to process the gem.

History

The ammonite was used as a traditional decorative object of the Blood Nation aboriginals. They continue to live in the Bearpaw shales of Alberta, Saskatchewan, and nearby U.S. states, and mine the gemstone to this day (Boswell, 50).

Ammolite was given gemstone status by the World Jewellry Confederation in 1981. It was the same year that commercial mining of the stone began. It is only the third newly named semi-precious stone in the last 50 years.

In 2004, ammolite was named the official gemstone of the Province of Alberta.

In 2007, ammolite also represented the City of Lethbridge as its official stone.

Healing Properties

Feng Shui followers refer to ammolite as the “Seven Colour Prosperity Stone”, with its colours of red, orange, green, yellow, and blue representing energy, creativity, wisdom, wealth and peace, respectively. It is also believed to help remove toxicity in the body.

Aboriginal tribes believe that ammolite is a stone of good luck. A legend tells of a woman who found an ammonite and brought it back to her tribe, who were hungry for food at the time. The tribe immediately discovered a herd of buffalo afterwards, and named the ammolite “The Buffalo Stone”.

Ammolite’s many colours is also believed to help relieve depression and bring peace of mind to oneself. Its circular shape is also believed to promote intuition and perception during the thought process.

Scientific info

Group: Mineral fossil
Formula: Calcium carbonate (CaCO3 + FeS2, SiO2)
Growth: Amorphous
Appearance: Shell brown, gray, or black; gemstone layer iridescence in all colours
Hardness (Moh’s Scale): 4.5 – 5.5
Specific Gravity: 2.60 – 2.85
Mine Locations: Canada, United States
Uses: Jewellry, ornamental, fossil study

References

International Gem Society. “Ammolite.” Accessed September 16, 2010.
Boswell, Randy, “Iridescent Alberta fossils hot items at auction,” Canwest News Service, March 24, 2009, 50.
Hall, Judy, The Crystal Bible 2. (Cincinnati, Ohio: Walking Stick Press, 2009), 201.