Psiloceras Ammonite Fossil Iridescent Shell Fragment Blue Lias Somerset UK Jurassic Rare Display Specimen Authentic Marine Fossil

Description

Highly Iridescent Psiloceras Ammonite Shell Fragment – Blue Lias, Somerset, UK

This highly iridescent Psiloceras ammonite shell fragment is a striking and rare fossil from the Blue Lias Formation of Doniford Bay, Watchet, Somerset, UK. Displaying vivid natural iridescence, this specimen captures the beauty of Jurassic marine life with shimmering colours that shift under light. The fossil shown in the photographs is the exact piece you will receive, carefully selected for its exceptional preservation and visual appeal.

Geological Age & Formation

This specimen dates to the earliest part of the Jurassic period, approximately 201 million years ago, within the Hettangian stage. The Blue Lias Formation is internationally renowned for its alternating layers of limestone and shale, deposited in a shallow marine environment following the end-Triassic mass extinction. Psiloceras is particularly significant as an index fossil for this time period and is closely associated with the Psiloceras planorbis Biozone, marking the very base of the Jurassic system.

Taxonomy & Classification

• Order: Ammonitida
• Superfamily: Psiloceratoidea
• Family: Psiloceratidae
• Genus: Psiloceras

Psiloceras was formally described by J. Sowerby in the early 19th century and is one of the earliest true ammonites to appear after the Triassic-Jurassic boundary.

Morphology & Iridescent Preservation

This shell fragment showcases the smooth, gently coiled structure typical of Psiloceras, which is characterised by its relatively simple morphology compared to later, more ornamented ammonites. Unlike heavily ribbed species, Psiloceras displays subtle growth lines and a clean shell profile.

What makes this specimen truly exceptional is its natural iridescence. This phenomenon occurs when the original aragonite shell material is preserved or replaced in such a way that it reflects light, producing vibrant colours such as blues, greens, and golds. These optical effects are highly sought after by collectors and add a unique aesthetic dimension to the fossil.

Depositional Environment

The Blue Lias sediments were formed in a calm, shallow sea with periodic changes in oxygen levels. These conditions allowed for excellent preservation of marine organisms, including ammonites, bivalves, and marine reptiles. Fine sedimentation helped protect delicate shell material, enabling rare preservation features such as iridescence to develop over millions of years.

Discovery & Professional Preparation

This fossil was discovered by our experienced team members, Alister and Alison, along the Somerset coastline. Following its recovery, the specimen was carefully cleaned, stabilised, and prepared by Alison to preserve both its structural integrity and its remarkable iridescent finish. The preparation process ensures the fossil is ready for display while maintaining its natural characteristics.

Authenticity & Provenance

This is a genuine Psiloceras ammonite fossil and includes a Certificate of Authenticity with a lifetime guarantee. Each specimen we offer is responsibly sourced and professionally prepared, providing confidence in both its authenticity and provenance.

Display & Collectability

Highly iridescent ammonite fragments are increasingly rare and highly desirable among collectors. This specimen is ideal for display, offering both scientific significance and visual impact. Its association with the earliest Jurassic ammonites makes it an important piece for collectors interested in evolutionary history, while its vibrant colours make it equally appealing as a decorative natural artwork.

Condition & Sizing

Please refer to the photographs for full sizing and condition details, as they form part of the description. The fossil is a carefully chosen piece, and the images accurately represent the exact specimen you will receive.