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 Ammolite
Technical Info
Chemical composition:
Variable, may include aragonite, calcite, silica, pyrite, or other
minerals
Color: Brilliant iridescent flashes of
green, gold, red, and sometimes blue or purple
Optics: R.1 1.52-1.67
Refractive Index: 1.52 - 1.68
Hardness: 4.5 - 5.5
Crystal structure: Amorphous
Specific gravity: 2.60 - 2.85
Heat Sensitive: Yes
Enhancements: Opticon and lacquer stabilization
Sources: Alberta, Canada, appears to be
the only known source of Ammolite, a 65 million year old fossilized
ammonite.
In 1981, Ammolite became recognized by CIBJO, (the
Colored Stones Commission.) It is the latest of only three new gemstones
introduced in the last 50 years. It is also only one of three organic
gemstones, (including amber & pearl.) It has been compared to
opal and has a superficial similarity to the Austrian mineral lumachelle
whose iridescence is also provided by the fossil ammonite carnites
floridus.
Ammonite shell is comprised primarily of aragonite, (the same mineral
that makes up pearls,) with trace elements of aluminum, barium, chromium,
copper, iron, magnesium, manganese, silicon, strontium, titanium and
vanadium.
Unlike most other gem, whose colors comes from light refraction, the
iridescent color of ammolite comes from interference with the light
that rebounds from stacked layers of thin platelets in the aragonite.
Ordered thick stacks for red gems, less ordered thinner stacks for
green and unordered, very thin stacks for blue ones.
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