Gem-quality Ammolite produces a spectacular display of iridescent color when
it is observed in reflected light. The colors of an individual stone can run
the full range of the visible spectrum or be limited to just one or two
colors. The color display can rival fine
opal and
labradorite in its
intensity and beauty.
Ammolite is a trade name given to a thin iridescent aragonite shell material
that is found on two species of extinct ammonite fossils (
Placenticeras
meeki and
Placenticeras intercalare). Other less-frequently
used trade names for Ammolite are "Calcenite" and "Korite." It is also known
simply as "ammonite shell."
Ammolite is a rare material. All of the world's commercial production comes
from a small area along the St. Mary River in southwestern Alberta, Canada.
There, two companies mine Ammolite from thin layers in the Bearpaw Formation
where the ammonite fossils are found.