IMPRESSIVE AND IRIDESCENT AMMONITE IN MATRIX
Placenticeras meeki
Late Cretaceous
Bearpaw Formation, southern Alberta, Canada
Over 90% of gem ammolite is found only in this locality in southern Alberta. The phenomenal colors were naturally created through the combination of millions of years of compression, and the mineralization of iron, copper and silica precipitated from volcanic ash. The shimmering colors of ammolite are the result of light refracting through, and rebounding from, thin platelets of aragonite, the primary constituent of the ammonite's shell, manifested on this 7 3/4 inch wide specimen in rich green, deep red, and fiery orange, shot through with gleaming golden yellow, in striking contrast to the irregular-shaped gray shale matrix, approximately 18 3/4 x 19 3/4 inches, with a wooden display stand.