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    Description

    FINE AND LARGE GEM AMMONITE
    Placenticeras meeki
    Late Cretaceous
    Bearpaw Formation, southern Alberta, Canada
    This is a superb example of one of the most attractive and sought-after of all fossils. The beautiful iridescent colors that shimmer throughout the shell are a natural but highly unusual form of fossilization. In most other places, the Aragonite-rich nacre (Mother-of-Pearl) of the Ammonite's shell is pseudomorphously replaced by Calcite or Pyrite. Not in the small Bearpaw formation, stretching over parts of Montana, Alberta and Saskatchewan, along the eastern slopes of the Rocky Mountains. The Ammonite's shell becomes tainted with trace elements such as Manganese, Strontium, Titanium, Barium and others, manifested in the dazzling colors displayed here. The resulting gemstone is called Ammolite. To the Blackfeet Indians of Montana, it is known as iniskim ("Buffalo stone"), where it has long been believed to have amuletic powers of use in healing and in attracting Buffalo. In 1981, Ammolite was accorded gemstone status by the World Jewellery Confederation. It is one of a few biogenic gemstones, like Amber and Pearl, and can be grouped with other shell-based marbles such as Lumachella, or "Fire Marble", which is formed from the fossilized shells of Clams or Snails. The present example is a first-class specimen, equally impressive when viewed from either side. It retains excellent shell coverage throughout, flashing with vibrant shades of green, red and gold, and preserving large areas of original shell structure in distinctive wavy lines. The specimen is flattened, as is usual, but two thirds of it retains a good amount of inflation, making for a highly dramatic and eye-catching display piece, 18½ inches in diameter, with wooden display stand.


    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.

    Auction Info

    Auction Dates
    May, 2012
    20th Sunday
    Bids + Registered Phone Bidders: 1
    Lot Tracking Activity: N/A
    Page Views: 2,556

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