Polished Ammonite from Madagascar (Cleoniceras) – Half-Shell with Unpolished Back – Lower Cretaceous – Fossil 110–120 Million Years Old
This listing features an original, fascinating half-shell of an extinct cephalopod—an ammonite of the genus Cleoniceras. The specimen comes from what are considered the world’s most beautiful paleontological sites in Madagascar and dates back to the Lower Cretaceous period (approximately 110–120 million years ago). The stone was intentionally cut along its axis of symmetry and polished to a high gloss on one side, allowing us to admire its intricate internal architecture. The other side (the back of the ammonite) has been left completely unpolished, preserving the natural, original character of this extraordinary fossil and creating a striking contrast in textures.
Specimen data and specifications (editable):
- ✓ Type: Natural fossil (Ammonite, Cleoniceras species)
- ✓ Geological age: Lower Cretaceous (approx. 110–120 million years)
- ✓ Dimensions: Approx. 150 x 125 x 16 mm
- ✓ Weight: Approx. 420 g
- ✓ Origin: Madagascar (Mahajanga region)
- ✓ Condition/Finish: Half polished on one side, natural and unpolished on the back
- ✓ Photos: Show the exact specimen being offered
What makes Madagascan Cleoniceras ammonites so special?
Ammonites from Madagascar enjoy international fame and are widely recognized by collectors as some of the most aesthetically pleasing and best-preserved fossils in the world. The key to their uniqueness lies in specific mineralization processes (known as permineralization) that have taken place over millions of years. The hollow air chambers, which the cephalopod used during its lifetime to control its buoyancy in the water, were slowly filled with mineral solutions over the course of eons. As a result, the interior of the shells has transformed into multicolored, honey-brown, crystalline calcite, often crisscrossed by intricate lobular lines (seams) that mark the boundaries of individual chambers. Once cut and polished, these natural partition lines create a mesmerizing, spiral pattern of perfect geometry.
Raw Nature vs. Jewelry Polish—Perfect Structural Harmony
The unique format of this specimen—a half-piece with a polished front and a raw back—allows you to fully appreciate nature’s duality. The front, glossy surface reveals the depth of the calcite crystals and a rich palette of earthy and amber hues. By turning the specimen over, you can feel the external structure of the original shell with its characteristic, ribbed growths. This contrast gives the ammonite an exceptionally authentic and dynamic appearance. It serves as a perfect, tangible lesson in natural history that will beautifully adorn a home display case or a science enthusiast’s desk, or make for a unique gift for a birthday, thesis defense, or anniversary.
Why should you add this specimen to your collection?
- 100% Authentic Fossil: We offer a fully original, fossilized ammonite shell, without any reconstructions or artificial casts. The natural crystalline structures guarantee its authenticity.
- Excellent preservation of the suture lines: The precise cut perfectly highlights the intricate patterns of the chamber partitions, enhancing the item’s scientific and aesthetic value.
- Handly size and versatile display: The dimensions and flat cut surface make it easy to place or display this half-shell without fear of damage. This ammonite makes a great decoration or gift.
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