Beautiful opalescent heart - Ammolite heart

An iridescent Ammolite heart from Canada, Alberta. The iridescence follows the natural lamellar structure of the original aragonite shell.

Aragonite shells are found in some mollusc genera, ammonites, some snails, and nacre-forming mussels. The aragonite modification of calcium carbonate is metastable; over very long geological periods, it converts into the thermodynamically more stable calcite modification.

Ammolite is a rare constellation in which the aragonite layer remained stable for 70 million years, due to geological pressure and the specific sediment chemistry of the Bearpaw Formation. In most other ammonitic deposits, the aragonite shell had long since been converted to calcite and the iridescence lost.

Heart-shaped sculpting is a classic jewellery tradition.

A Canadian collector's item with documented metastable aragonite preservation over 70 million years.