Ammonite - Fossilised shell - 54 mm - 110 mm

Exceptional High-Grade Polished Ammonite from Madagascar

This stunning Madagascar ammonite fossil, beautifully polished to reveal its intricate suture pattern, originates from the world-famous Mahajunga region. Dating to the Cretaceous period, this genuine specimen showcases millions of years of natural history preserved within its spiral chambers. The ammonite photographed is the exact piece you will receive, carefully chosen for its exceptional quality, rich colouring, and striking structural detail. Every fossil we offer is 100% genuine and includes a Certificate of Authenticity.

Geological Origin and Cretaceous Setting

The Mahajunga region of Madagascar is renowned for producing some of the finest ammonites in the world. During the Cretaceous, this area lay beneath warm, nutrient-rich tropical seas thriving with marine life. Over time, ammonites fell to the seafloor where they were rapidly buried by fine sediments. This environment promoted excellent fossil preservation, allowing their shells to mineralise and retain exquisite internal structures. As the sediments compacted and lithified, the ammonites were preserved in remarkable detail, later to be revealed through expert polishing. These polished Madagascan ammonites are globally admired for their vibrant colouration, often including warm earth tones, subtle iridescence, and beautifully preserved suture lines.

Fossil Type and Scientific Significance

Ammonites were marine cephalopods related to modern squids and nautiluses. Their shells contain complex internal partitions called sutures, which reflect the animal’s evolutionary adaptations and provide palaeontologists with valuable insights into classification and lineage. Madagascan ammonites from Mahajunga are known for their particularly ornate suture patterns, making them excellent examples for both study and display. These fossils are representative of the diverse marine ecosystems of the Cretaceous and contribute important data to biostratigraphic research across the prehistoric Tethys Ocean.

Morphological Features

This specimen displays the classic ammonite form: a tightly coiled planispiral shell divided into chambers that once held gas or fluid to control buoyancy. The polishing reveals the internal suture system in exceptional clarity, showing elaborate, fern-like patterns across the surface. These sutures mark the contact points between the shell wall and internal septa, creating intricate natural designs that collectors highly value. The surface exhibits warm mineral tones ranging from deep browns to honey and caramel shades, occasionally accompanied by subtle opalised flashes. The fossil retains excellent whorl definition, showcasing both the geometry and the natural symmetry of the original shell.

Depositional Environment

Cretaceous seas around Madagascar provided ideal conditions for fossilisation. Calm marine basins allowed shells to settle and become swiftly covered by fine sediment, protecting them from erosion and scavengers. Over millions of years, mineral-rich groundwater permeated the shells, replacing organic material and enhancing the colours and textures for which Madagascan ammonites are famous. The remarkable preservation of suture patterns is a testament to the gentle depositional conditions and stable chemical environment of the region’s ancient seabeds.

Provenance and Collector Appeal

Madagascar ammonites are among the most sought-after decorative and scientific fossils available today. Their combination of natural beauty, geological significance, and artistic patterning has made them popular with fossil collectors, interior designers, and museums worldwide. This high-grade polished specimen from Mahajunga offers exceptional aesthetic appeal, showcasing vivid suture patterns and excellent structural preservation. Its authenticity, craftsmanship, and geological importance make it an outstanding addition to any collection, whether for display, education, or appreciation of Earth’s ancient oceans.

Size: 110 x 85 x 54mm
Weight: 626g