Fossils for Sale - High-quality BRITISH and WORLDWIDE Fossils. An impressive selection of fossils, including Ammonites, Trilobites, Belemnites, Fossil Fish, Fossil Shark Teeth, Fossilised Insects in Amber, Dinosaurs, and Reptiles. UK Fossils was formed in 1988 and collects and preps our own fossils in the heart of the Jurassic Coast, collecting fossils from Lyme Regis, Charmouth and Somerset. Our passion for fossils is reflected in our carefully curated collection, which includes some of the rarest and most unique specimens available.

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Iridescent Polished Ammonite Fossil from the Cretaceous of Madagascar Genuine Display Specimen COA

Iridescent Polished Ammonite Fossil from the Cretaceous of Madagascar Genuine Display Specimen COA

Original price was: £42.00.Current price is: £21.00.

All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity

**Please note: Some Fossils maybe propped up for photo purposes**

Specimen: Iridescent Ammonite

Location: Madagascar

Age: Cretaceous

Size (picture scale cube=1cm):   75 x 20 x 59mm (2.95 x 0.79 x 2.32 inches)

These amazing Ammonites are iridescent, with a unique red glow, shining a spectrum of colours under light. They come from Madagascar, and are Cretaceous in age.

ACTUAL AS SEEN: The image shows the EXACT specimen you will receive. The specimen has been carefully hand selected and photographed. Measurements are as accurate as possible, though be aware measuring precise dimensions can be difficult from irregular shaped items. Whilst we portray colours as close to life-like as we can, colours will vary if taken in sunlight, indoors, from monitor to monitor and device to device. Once this specimen is sold, we will update this listing with new similar selected item, with a new photo and dimensions.

 

What is a fossil?

The word Fossil used to be defined as ‘something dug up’. Now-a-days it generally means ‘The remains or trace evidence of prehistoric life’. The study of fossils is called palaeontology; someone who collects and studies them is called a palaeontologists. Fossils can be as tiny as a grain of pollen or a seed for e.g. or as huge as a limb bone from a giant dinosaur. For animal or plant remains to have become ‘fossilised ‘, they must go through a certain process that preserves them for up to millions of years after they have died. Usually it is only the hard parts of plants and animals that survive this long process.

How Fossils Formed

 

The most common method of how fossils formed is once an animal or plant dies, it falls to the ground, and is covered by sediment. This is often sediments brought from water. In the diagram above, the ammonite died in a river, and sediments over time covered the ammonite (shown in the second diagram). Finally after hundreds of thousands, or millions of years, the land is eroded and the fossil can be seen.

Of the vast amount of prehistoric life that died, it is only a tiny amount that has survived the fossilisation process. The conditions when the majority of life died were just not right at that time, to preserve them. Most fossils are found in sedimentary rocks which were formed from the sediments of rivers, lakes and seas. The majority of the animal and plant fossils we find today, had originally died near these areas, got broken up and deposited on the beds of the rivers, lakes and seas. The sediments covered them and over time some of the layers grew so thick that many of them got crushed. The sediments compacted and over time and turned to rock. The rocks shifted, moved and became exposed to the elements. This process can take up to several hundred million years. Now as the rocks erode or are quarried for e.g. the fossils become exposed and can be collected.

The Best conditions for Fossilisation

1. The quick burial of animal remains in moist sediments. This prevents scavengers from eating and bacteria from decaying them.

2. The quick burial in volcanic ash. Many dinosaur bones in the American west have been found buried in volcanic ash.

3. The presence of hard body or plant parts .Teeth, bones , shell and wood for e.g.

4. Unchanging temperature conditions.

5. Ground water that is heavily mineralised.

6. Sediments that are very fine make a better burial than coarser gravels.

7. Calm conditions, so that remains are not broken up (by wave or currant action for example).

(Actual as seen)

Only 1 left in stock

SKU: FP9782 Category:

Description

Authentic Iridescent Polished Ammonite – Cretaceous, Madagascar

This listing presents a genuine iridescent polished ammonite fossil from the Cretaceous Period, sourced from Madagascar, a world-renowned locality for beautifully preserved and naturally colourful ammonites. The specimen has been carefully selected for its strong iridescence, balanced form, and overall display quality. The photographs show the exact fossil you will receive, with full sizing details provided in the listing images. As with all our fossils, this piece is 100% genuine and supplied with a Certificate of Authenticity.

Geological Age and Setting – Cretaceous Marine Seas

The Cretaceous Period (approximately 145–66 million years ago) was a time of expansive shallow seas and extraordinary marine biodiversity. During this era, Madagascar lay within warm tropical waters connected to the ancient Tethys Ocean. These conditions supported vast populations of ammonites, which thrived as active nektonic predators in open marine environments.

Fine-grained marine sediments rapidly buried ammonite shells after death, protecting them from erosion. Over millions of years, mineral-rich waters replaced and preserved the original shell material. In some specimens, the original nacreous shell layers were preserved and later enhanced through careful polishing, revealing spectacular natural iridescence.

Fossil Type – Iridescent Polished Ammonite

Ammonites were extinct marine cephalopods closely related to modern squid and cuttlefish. Their coiled shells were divided into chambers that regulated buoyancy, allowing them to occupy a wide range of marine depths. The specimen offered here has been professionally polished to reveal the internal shell structure and the naturally occurring iridescent layers within the fossilised shell.

Notable features commonly visible on iridescent polished ammonites include:

  • Vivid colour play, with flashes of green, gold, red, and blue

  • Clearly defined spiral coiling, preserved in three dimensions

  • Distinct chamber structure, visible through the polished surface

  • Smooth, high-gloss finish, enhancing natural colour and detail

  • Strong visual symmetry, ideal for display

The iridescence results from microscopic layering within the fossil shell that refracts light, producing shifting colours depending on viewing angle.

Madagascar – A Premier Source of Iridescent Ammonites

Madagascar is internationally recognised as one of the finest sources of Cretaceous ammonites, particularly those exhibiting natural iridescence. The island’s sedimentary basins provided the ideal chemical and physical conditions for preserving shell material capable of producing this colour effect.

Specimens from Madagascar are widely collected by museums, private collectors, and interior designers due to their combination of scientific importance and striking natural beauty. Polished examples are especially sought after for display, as they highlight features not visible in unprepared fossils.

Scientific and Display Significance

Iridescent ammonites are valued for both their palaeontological importance and aesthetic impact. They provide insight into ancient marine ecosystems while also serving as dramatic natural art pieces formed by geological processes over tens of millions of years.

This specimen is well suited for:

  • Fossil and natural history collections

  • Educational and teaching displays

  • High-quality interior décor

  • Gifts for fossil and geology enthusiasts

The durability of the fossil and polished surface ensures long-term stability when properly displayed.

Your Genuine Fossil Specimen

  • Fossil Type: Iridescent polished ammonite

  • Geological Age: Cretaceous Period

  • Locality: Madagascar

  • Authenticity: 100% genuine fossil with Certificate of Authenticity

  • Condition: Carefully selected, polished display specimen

  • Sizing: Full measurements shown in listing photographs

  • Exact Specimen Shown: You will receive the fossil pictured

This iridescent polished ammonite from Madagascar offers a rare combination of geological authenticity, vibrant natural colour, and refined presentation. It is a striking and timeless piece that brings the beauty of ancient Cretaceous seas into any fossil collection or display.

Additional information

Weight 50 g
Era

Jurassic
Origin

Madagascar

Jurassic Information

The Jurassic Period (201–145 million years ago) was the golden age of dinosaurs, with iconic species like Brachiosaurus, Stegosaurus, and Allosaurus dominating the land. It was a time of warm, humid climates, with high sea levels that created vast shallow seas, supporting abundant marine reptiles, ammonites, and early coral reefs. The first birds, such as Archaeopteryx, evolved from small theropod dinosaurs, while early mammals remained small and nocturnal. Lush forests of cycads, conifers, and ferns covered the land, providing food for giant herbivores. The breakup of the supercontinent Pangaea accelerated, shaping Earth's geography and setting the stage for the diverse ecosystems of the Cretaceous.

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