Ammonites on Composite Matrix
Ammonites on Composite Matrix
- Ethically Sourced
- Secure payments
- Small Business/Artisan Made
- Packed With Recycled Materials
- Low stock - 1 item left
- Inventory on the way
Ammonite info - Quenstedtoceras Callovian, Middle Jurassic
Moscow Basin
5x4.5x1"
Iridescent ammonite fossils are extraordinary remnants of ancient marine cephalopods, displaying a captivating, rainbow-like shimmer. This iridescence arises from the preservation of the shell’s original microstructure, which diffracts light. Beyond their visual appeal, these fossils hold scientific importance, offering insights into the environmental conditions under which they formed and were preserved.
Ammonites, including those with iridescent shells, had a planispiral shell, meaning it coiled in a single plane. This spiral structure featured multiple whorls—each a complete 360-degree turn of the shell. Composed primarily of aragonite, a crystalline form of calcium carbonate, ammonite shells sometimes retained their original composition, enabling the iridescent effect seen in fossils.
The iridescence results from the preservation of the nacreous (mother-of-pearl) layer, which consists of microscopic, plate-like aragonite crystals arranged in an orderly structure. When light interacts with these layers, it is diffracted and reflected, producing the shimmering effect. The colors observed in iridescent ammonites range from vivid blues and greens to deep reds and purples, depending on the thickness and arrangement of the aragonite layers.
For this iridescence to be preserved, specific conditions must be met during fossilization:
- Rapid Burial: Immediate sediment coverage after death prevents decomposition and shell damage.
- Low Oxygen Environment: An anaerobic setting slows organic decay and protects the aragonite structure.
- Stable Geochemical Conditions: Consistent sediment and water chemistry prevent the aragonite from dissolving or being replaced by other minerals.
Iridescent ammonite fossils serve as breathtaking relics of prehistoric marine life. Their striking beauty stems from the preserved nacreous layer and its light-diffracting aragonite crystals. Admired by collectors and paleontologists alike, these fossils not only captivate with their aesthetic allure but also provide valuable scientific insights into ammonite biology and the fossilization process. Ongoing research into these specimens continues to deepen our understanding of ancient marine ecosystems and the conditions that allowed such remarkable preservation.
