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    Description

    FINE DOUBLE GEM AMMONITE PLAQUE
    Placenticeras meeki
    Upper Cretaceous
    Bearpaw Formation, Alberta, Canada

    The ammonites found in the oceans covering this small area of North America 65-100 million years ago are amongst the most sought-after of all fossils. All ammonites have a layer of nacreous mother-of-pearl (hexagonal platelets of aragonite) lining their shells, but only the Placenticeras sp., through the combination of millions of years of compression and the mineralization of iron, copper and silica which precipitated from the bentonite sediment of volcanic ash, have been transformed into this beautiful precious gem stone ammolite. It is one of several biogenic gemstones, like amber and pearl, and can be grouped with other shell-based marbles such as lumachella, or "fire marble", formed from the fossilized shells of clams or snails. It is far more striking than these other substance, however, and was accorded gemstone status by the World Jewelry Federation in 1981. This fantastic plaque boasts two examples, measuring 14¼ and 6 inches in diameter. The gray stone matrix provides the perfect ground to offset the shimmering display of iridescent green, yellow and red that flashes across the shells, enlivened by highlights of the much rarer blue and purple shades. The plaque itself measures 39½ x 31 inches and is presented on a custom metal display stand.


    Estimate: $28,000 - $32,000.

    Condition Report*: Condition report available upon request.
    *Heritage Auctions strives to provide as much information as possible but encourages in-person inspection by bidders. Statements regarding the condition of objects are only for general guidance and should not be relied upon as complete statements of fact, and do not constitute a representation, warranty or assumption of liability by Heritage. Some condition issues may not be noted in the condition report but are apparent in the provided photos which are considered part of the condition report. Please note that we do not de-frame lots estimated at $1,000 or less and may not be able to provide additional details for lots valued under $500. All lots are sold "AS IS" under the Terms & Conditions of Auction.

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    Auction Info

    Auction Dates
    May, 2009
    17th Sunday
    Bids + Registered Phone Bidders: 1
    Lot Tracking Activity: N/A
    Page Views: 1,038

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