Ammonite (Placenticeras meeki), Bearpaw Formation, Oldman River, Near Lethbridge, Alberta (16.5" diameter)

Our inaugural listing of the pinnacle of ammonite fossils: a Placenticeras meeki from the Bearpaw formation of Alberta! Having authored the keystone technical paper on this topic (see Mychaluk et al, 2001 in Gems & Gemology), I can confidently say this is a world-class specimen based on colouration, completeness, definition of details and minimal restoration and repair. Furthermore, this specimen measures at an impressive 16.5" diameter!

In our 2001 research, my co-authors and I discovered a correlation between colour and the integrity of the micro-crystalline structure of the ammonite. More simply said, we found that the more common colours (such as reds & browns) had the most robust crystal structure, while rare blues and purples were quite delicate. We concluded that the more delicate the crystal structure, the more unlikely it would survive the ravages of geologic time, hence the rarity of blues and purples. These rare colours are the most sought after and certainly help drive valuations upward.

Our current offering displays an excellent array or colours. One side has the classic desirable shade of green, nicely accented by orange, yellow and red with a hint of blue and purple. However the opposite side, along with green, is dominated by the rare blues and purples. Which side to display? Certainly a good problem to have!

Colour is obviously important but this specimen is also essentially complete with good definition. First let's discuss the keel. That is the outermost diameter of the shell. It is fully intact and sharply-defined with minimal damage. Keels are are typically crushed and are commonly restored - but not here. Next we can clearly see linear features on the shell which is part of the external decoration of the animal. External features herald the completeness of a specimen. More often than not, the internal features are more evident on these fossils. The internal chambers within ammonites are quite distinctive and their patterns are called suture lines (paleontologists use these to help identify the various species of ammonites). Yet if a specimen is covered in suture lines that means most of the external shell has been lost through erosion or collection damage and typically has a lack of colour. Looking back at our offering, only the "top" of the specimen displays the crenulated suture lines whereas most of the specimen shows the nice, elegantly-curved lines of the external shell. 

Further, note the distinctive shape at the end of the shell whorl (the widest end). This indicates that it is complete; this distinctive shape being the "living chamber" where the squid-like animal actually lived (the remainder of the shell stored air to assist with buoyancy and mobility during life). Since this end of the shell was "open" it is usually the most damaged as a fossil and most need to be restored in some manner but our specimen is wonderfully complete. Again I will also state the diameter: a whopping 16.5"!

The evidence here shouts that this fossil has been exquisitely preserved yielding a large and wonderfully complete, beautiful example of, arguably, the world's most impressive ammonite.

This specimen was extracted from the Bearpaw Formation shale. These are Late Cretaceous shallow sea deposits believed to be 66 - 75 millions years old. Quality pieces like this one are more-specifically from "Zone 4" or the "Blue Zone" of the Bearpaw, a fabulously-rich interval found in the St Mary and Oldman river valleys near Lethbridge, Alberta. Our specimen was legally-mined and comes with a proper Disposition Certificate from the Province of Alberta, and is therefore eligible for sale and export. 

Please enquire if you have an questions or require further detail.