Details
From the Upper Cretaceous, Bearpaw formation (75-72 million years ago), the 20-inch specimen of Placenticeras interclare showing iridescence of red, green, yellow and orange to both sides, with blues to one; some infills and restorations.

20in. (51cm.) diameter
Special notice
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This lot will be removed to Christie’s Park Royal. Christie’s will inform you if the lot has been sent offsite. Our removal and storage of the lot is subject to the terms and conditions of storage which can be found at Christies.com/storage and our fees for storage are set out in the table below - these will apply whether the lot remains with Christie’s or is removed elsewhere. Please call Christie’s Client Service 24 hours in advance to book a collection time at Christie’s Park Royal. All collections from Christie’s Park Royal will be by pre-booked appointment only. Tel: +44 (0)20 7839 9060 Email: cscollectionsuk@christies.com. If the lot remains at Christie’s it will be available for collection on any working day 9.00 am to 5.00 pm. Lots are not available for collection at weekends.
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Lot Essay

The opal like iridescence of these ammonites from Alberta, Canada has been termed ammolite and since 1981 has had the status of a gemstone. The shimmering, metallic colours were caused by the combination of millions of years of compression and the mineralization of iron, copper and silica which precipitated from volcanic ash. The opalescent layers of colour are particularly prized in the Chinese philosophical system of Feng-Shui.

The ammonites are a group of molluscs that lived in the seas from the mid-Devonian (approximately 400 million years ago) to the end of the Cretaceous (65 million years ago). The sequence of events that famously killed off the dinosaurs also drove the ammonites to extinction

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