Red Opalescent Cleoniceras Ammonite from the Cretaceous...

Lower Cretaceous (145–100.5 million years) - Excellent Cleoniceras with Red Opal Fluorescence — This lot presents a magnificent specimen of ammonite of the genus Cleoniceras, from the famous Cretaceous Madagascar deposits. The fossil, witness to a marine ecosystem more than 100 million years old, has been masterfully cut and polished to reveal its intricate internal architecture. The most fascinating feature of this piece is its vibrant iridescence, with dominant flashes of deep red that have earned it the commercial name "Fire Ammonite." It is an object that unites the scientific rigor of paleontology with the incredible aesthetic of a gem created by nature. Direct observation of the specimen reveals a nearly perfect logarithmic spiral, an icon of natural geometry. The mirror-polished surface acts as a window into the past, allowing a view into the chambers (or phragmocone) that the ancient cephalopod used to regulate its buoyancy. These chambers appear filled with deposits of crystalline calcite and other sedimentary minerals, creating a mosaic of colors ranging from earth brown tones to pearl gray. What makes the specimen exceptional are the complex and delicate sutural lines, the junctions between the chamber walls and the outer shell. In this Cleoniceras, they form a filamentous and rugged pattern, a sign of notable biological evolution. The chromatic phenomenon that defines this piece is spectacular. When light hits the surface, intense bursts of ruby red and orange illuminate with surprising vividness. This is not pigmentation, but a structural optical effect known as iridescence, caused by the preservation of the original aragonite layer that made up the shell nacre. During fossilization, this layer was preserved in extremely thin laminas. Light passing through and reflecting from these layers undergoes a diffraction and interference process that splits white light into its constituent colors. It is the same physical principle that yields the changing colors of noble opal, turning this fossil into a true organic gem. Ammonites of the genus Cleoniceras lived during the Albian, a stage of the Early Cretaceous, about 113–100.5 million years ago. The Madagascar deposits are renowned worldwide for the exceptional state of preservation of fossils, often with the original shell partially or totally preserved, as in this case. The fossilization process in an anoxic, mineral-rich environment allowed the delicate shell structure not to be destroyed, but slowly permineralized, thus preserving the incredible optical effect of nacre. For a collector, an ammonite like this represents a piece of great value. The combination of species (Cleoniceras), provenance (Madagascar), era (Cretaceous) and, above all, the quality of the “fire” iridescence places it among the most desirable specimens. Beyond its scientific interest, it is an object of extraordinary decorative beauty. Its sculptural shape and changing colors make it perfect as a visual focal point in a modern Wunderkammer, on a studio desk, or in a library. Owning a fire ammonite means safeguarding a time capsule, a tangible link to the deep history of our planet. Technical details Name: Fossil ammonite (Genus: Cleoniceras) Classification: Cephalopoda Provenance: Madagascar Geological Period: Cretaceous (ca. 145–100.5 million years) Dimensions: 102 x 86 x 25 mm Weight: 254 g Condition: Natural specimen, cut and polished to expose the inner chambers and iridescence.

Estimate:£125.77

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