Beschreibung:

Placenticeras costatum Upper Cretaceous Bearpaw Formation, Southern Alberta, Canada Coveted by collectors the world over, the 70 -75 million-year-old ammonite specimens from the Bearpaw Formation display a spectacular palette produced by light interference by the shell’s layers. The flashing reds, oranges, golds and vibrant greens of the present exceptionally well preserved ammonite are produced not by opalization as is often thought, but by the ammonite’s own mother-of-pearl layer which has been fossilized. The resulting brilliant material is known as ammolite, one of only two fossil materials classified as gemstones (the other being amber.) This beautifully inflated and complete example, in matrix, also exhibits some blue and purple coloration along the outer edge, which is highly prized by collectors. A spectacular piece; the luminous colors show in dramatic contrast to the deeply colored matte shale. Measures approximately 38in x 35in, specimen measures 20in.