Ammolite is the opalised version of ammonite fossils. It is a colourful gemstone that is organic in nature and formed from fossilised shells that are composed mainly of aragonite. Aragonite is the same material that is contained in a pearl’s coating. Ammolite has an iridescence that is caused by light’s interaction with the layered structure of the shell. The iridescent colours are usually red and green, but other colours may be present. Ammolite is a relatively new gemstone, having only been on the market since 1969. It is found in Canada, and the USA.
