Sergo Ordzhonikidze Russian State Geological Prospecting University, Moscow, Russia:

D. A. Petrochenkov, Associate Professor, Candidate of Geologo-Mineralogical Sciences, p-d-a@mail.ru
V. V. Kulikov, Pro-Rector of Educational Activities, Professor, Doctor of Engineering Sciences
A. K. Litvinenko, Head of Chair, Doctor of Geologo-Mineralogical Sciences
L. D. Onikienko, Professor, Doctor of Geologo-Mineralogical Sciences

The current world market widely presents ammonites for the collecting and interior decoration purposes. In the last decades, jewellery and souvenir style ammonites enjoy growing demand. This article considers the methods of mining and processing of Canadian gem-quality ammonites, as well as the detailed study results on their gemological characteristics. Canadian ammonites are popular on the market owing to their fossil nacre and colored iridescence. Fragments of mother-of-pearl layer are used for making cabochons known under the commercial name of ammolite. Iridescence of ammolite is associated with the remaining lamellar aragonite layers of ammonite walls. The color of iridescence is connected with the structure and size of aragonite microcrystals. The experience of mining and processing of ammonites in Canada can be useful for Russia holding considerable reserves of the mineral.

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