ammolite
Sign in to saveAmmolite is an organic gemstone found primarily along the eastern slopes of the Rocky Mountains of North America. It is commonly unearthed by natural erosion or through the process of various mining practices, within the perimeter of an ancient sea bed called the Western Interior Seaway. 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.
Key facts
- Mineral.name
- Ammolite
- Mineral.category
- fossilized, mineralized Ammonite shell
- Mineral.boxbgcolor
- b34f4d
- Mineral.boxtextcolor
- fff
- Mineral.image
- Ammolite.jpg
- Mineral.caption
- Unprocessed sample of ammolite; a "dragon skin" pattern is apparent
- Mineral.formula
- aragonite polymorph, with minor amounts of calcite, pyrite, silica, and other impurities
- Mineral.color
- Gray to brown, can be radiant blue, with primarily red to green iridescence.
- Mineral.cleavage
- no true cleavage
- Mineral.fracture
- uneven to granular
- Mineral.mohs
- 3.5 - 4.5
- Mineral.luster
- greasy to dull
- Mineral.polish
- vitreous
- Mineral.refractive
- usually 1.52 - 1.68 (varies with mineral content)
- Mineral.opticalprop
- anomalous aggregate reaction
- Mineral.birefringence
- 0.135 - 0.145
- Mineral.pleochroism
- none
- Mineral.fluorescence
- variable
via Wikipedia infobox
Article
11 sectionsContents
- Properties
- Origin
- Occurrence
- Extraction
- Gemstone quality
- Treatments
- Imitations
- Use in jewelry
- Footnotes
- References
- External links
Ammolite is an organic gemstone found primarily along the eastern slopes of the Rocky Mountains of North America. It is commonly unearthed by natural erosion or through the process of various mining practices, within the perimeter of an ancient sea bed called the Western Interior Seaway. 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 (CIBJO), the same year commercial mining of ammolite began. It was designated the official gemstone of Lethbridge, Alberta, Canada in 2007, and was subsequently designated as Alberta's official gemstone in April 2022.