Ammonite / Ammolite (Halpern Coll.)

Item Description

Here is a richly colored, totally iridescent, fire-red mineralized Ammonite from the Cretaceous beds of Alberta, Canada. The piece is roughly in the shape of a "J" and has the iridescent appearance of the best Mexican fire opal, but is much more intense and it's mixed with some bright green and red-orange colors as well. The surface is glossy smooth with some preserved Ammonite nodes on the shell. It looks as though the shell has been coated with an epoxy resin. Jack Halpern's label indicates that it originates from the Upper Cretaceous Bearpaw Shale and although he lists the species as a "variety" it is really a Placenticeras intercalare. We are truly honored to present this specimen from another lot of deaccessions from the collection of Jack Halpern of San Francisco (for more info: https://www.irocks.com/the-jack-halpern-collection). This is a really nice one, of a good size. It is actually very difficult to find choice examples in this size range! For those who want to read the details, although we usually call these "opalized Ammonites" it is a bit more complicated: This technically is not a mineral/gem but a fossil of the original calcium carbonate shell of the animal within. From Wikipedia: "An iridescent opal-like play of color is shown in fine specimens, mostly in shades of green and red; all the spectral colors are possible, however. The iridescence is due to the microstructure of the aragonite: unlike most other gems, whose colors come from light absorption, the iridescent color of ammolite comes from interference with the light that rebounds from stacked layers of thin platelets that make up the aragonite. The thicker the layers, the more reds, and greens are produced; the thinner the layers, the more blues, and violets predominate. Reds and greens are the most commonly seen colors, owing to the greater fragility of the finer layers responsible for the blues. When freshly quarried, these colors are not especially dramatic; the material requires polishing and possibly other treatments in order to reveal the colors' full potential" This piece shows beautiful red, green, yellow, and gold flashes when rotated in the light. As price guidance goes, honestly these are not something we often deal in because very few specimen-worthy examples exist in what I would call a normal size for collectors. Too many of these are big, or partial. Very few actually work as fine specimens, and this is one of those few. I can say that Jack paid $2000 for this, many years ago, for the special quality of color and shape, and had long wanted a good one for the collection. While big ones are available, few smaller examples of this size range seem to survive and make it to collectors. The jewelry market for this material is too voracious and they cut them into pieces. 89 grams here, of prime carving material.