Promicroceras Golden Pyrite Ammonite Fossil Jurassic Dorset UK Black Ven Marls Lower Lias Stonebarrow Cliff Charmouth Lyme Regis

Description

Genuine Golden Pyrite Promicroceras Ammonite from the Jurassic Coast

Offered here is a beautifully preserved Promicroceras golden pyrite ammonite fossil, collected from the renowned Black Ven Marls at Stonebarrow Cliff, Charmouth, part of the world-famous Jurassic Coast at Lyme Regis, Dorset, UK. This is a carefully chosen natural specimen, and the photographs show the exact fossil you will receive, with full sizing clearly visible in the images.

This fossil is supplied with a lifetime Certificate of Authenticity on a generic card, guaranteeing it as a genuine natural specimen. The ammonite has been professionally cleaned, prepared, and stabilised to enhance detail while preserving its original geological character.

Fossil Type and Species – Promicroceras

Promicroceras is a classic ammonite genus from the Lower Jurassic (Lower Lias), belonging to the Order Ammonitida, Superfamily Psiloceratoidea, and Family Eoderoceratidae. These ammonites lived during the Sinemurian Stage, approximately 195 million years ago, when warm, shallow seas covered much of southern Britain.

Promicroceras is highly regarded in Early Jurassic biostratigraphy and is often used as an index fossil due to its distinctive morphology and stratigraphic significance. Specimens from Dorset are especially prized for their excellent preservation and historical importance in British palaeontology.

Morphology and Diagnostic Features

This specimen displays the defining characteristics of Promicroceras, including:

• Tight, planispiral coiling with strong symmetry
• Bold, evenly spaced radial ribs across the shell flanks
• A compact whorl profile with clear growth lines
• Excellent surface definition preserved in mineral detail

These features make Promicroceras an instantly recognisable and visually appealing ammonite, ideal for both collectors and educational collections.

Golden Pyrite Preservation

One of the most striking aspects of this fossil is its natural golden pyrite mineralisation. Pyrite, often known as “fool’s gold,” formed when iron and sulphur combined under low-oxygen conditions within the Jurassic seabed sediments. Over millions of years, pyrite replaced or infilled the original shell material, preserving intricate surface detail while producing a shimmering metallic gold finish.

Golden pyrite ammonites from the Black Ven Marls are especially sought after because they combine strong scientific value with exceptional aesthetic appeal. The reflective surface highlights the ribbing and shell contours, making this specimen a standout display fossil.

Geological Context – Black Ven Marls, Lower Lias

The Black Ven Marls were deposited in a quiet offshore marine environment during the Early Jurassic. Fine-grained muds accumulated on the sea floor, allowing ammonites and other marine organisms to be rapidly buried and fossilised under conditions favourable for pyrite formation.

Stonebarrow Cliff and Charmouth lie within the UNESCO World Heritage-listed Jurassic Coast, one of the most important fossil regions in the world. Fossils from this locality have been collected and studied for over two centuries and remain central to understanding Jurassic marine ecosystems, sedimentology, and ammonite evolution.

Collector, Educational, and Display Value

Promicroceras ammonites are highly desirable for:

• Fossil and ammonite collectors
• Mineral collectors attracted to pyrite preservation
• Educational and teaching collections
• Display cabinets and curated fossil shelves

The combination of compact size, bold ribbing, and golden pyrite mineralisation makes this specimen both visually impressive and scientifically meaningful.

Authenticity and Provenance

• Fossil type: Promicroceras ammonite
• Preservation: natural golden pyrite
• Formation: Black Ven Marls, Lower Lias
• Geological age: Lower Jurassic, Sinemurian Stage
• Locality: Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, UK
• Certificate: Lifetime Certificate of Authenticity included

This fossil represents a genuine piece of Dorset’s Jurassic seabed, preserving a marine animal that lived nearly 200 million years ago, and offers a rare opportunity to own a beautifully preserved golden pyrite ammonite from one of the world’s most celebrated fossil localities.