RARE Lunuloceras lunula iridescent Fossil Ammonite Jurassic Lower Callovian Russia

Description

Rare Lunuloceras lunula Iridescent Fossil Ammonite from Russia

This listing features a rare and genuine Lunuloceras lunula Fossil Ammonite from the Lower Callovian stage of the Jurassic period, discovered in Russia. This exceptional ammonite displays a beautiful iridescent nacreous shell, with natural rainbow-like colours that glisten under light. Such iridescent ammonites are highly prized among fossil collectors for their combination of scientific significance and striking visual appeal.

The specimen shown in the photographs is the exact fossil you will receive, with a 1 cm scale cube for accurate sizing reference. Every fossil we sell is 100% genuine, and this piece is supplied with a Certificate of Authenticity for complete peace of mind.

Geological Setting and Age

The Lower Callovian stage of the Middle Jurassic, dating to around 165 – 163 million years ago, was a time of significant diversification in ammonite faunas across Europe and Russia. Ammonites from this age are critical to refining biostratigraphic zones, as their rapid evolutionary rates make them ideal for correlating rock layers across vast regions.

This particular ammonite comes from Russian deposits renowned for their high-quality preservation. During the Jurassic, shallow epicontinental seas covered much of the region, providing an ideal habitat for ammonites. Fine marine sediments created excellent fossilisation conditions, protecting delicate shell layers and occasionally preserving nacreous iridescence.

Scientific Classification and Importance

This specimen is identified as Lunuloceras lunula, a species within the order Ammonitida, superfamily Perisphinctoidea, and family Cosmoceratidae. Members of this family are recognised for their ribbed, evolute shells and play a key role in Jurassic biostratigraphy.

Lunuloceras lunula is an important ammonite for identifying horizons within the Lower Callovian. Its relatively restricted stratigraphic occurrence allows geologists and palaeontologists to date the layers it is found in with precision. As a result, specimens such as this one have both scientific value in stratigraphy and collector value in palaeontology.

Morphology and Distinctive Features

The morphology of Lunuloceras lunula is characterised by:

• Evolute coiling, with earlier whorls visible from the side.
• Strong radial ribbing, a hallmark of its shell structure.
• A compressed and slightly keeled whorl cross-section.
• Iridescent nacre preservation, producing shimmering colours under light.

These features make it a visually appealing specimen as well as an excellent example of its species, demonstrating the classic traits of Lower Callovian ammonites.

Depositional Environment

The marine environment of the Jurassic Callovian seas provided ideal conditions for ammonite populations. These seas were shallow, warm, and nutrient-rich, supporting diverse marine life. Ammonites such as Lunuloceras thrived in these ecosystems, where they formed a critical part of the marine food chain.

Rapid burial in fine-grained sediments protected their shells from erosion and scavenging, and under certain geochemical conditions, the nacreous shell layers fossilised with brilliant iridescence. These rare conditions explain why iridescent ammonites are far less common than typical non-iridescent fossils.

Collector and Display Value

This Lunuloceras lunula iridescent ammonite is not only a scientifically valuable fossil but also an exquisite display piece. Its natural iridescence gives it a gemstone-like quality, making it a stunning addition to any fossil collection, museum display, or private showcase.

Collectors particularly value specimens that combine:

• Index fossil significance for stratigraphic dating.
• Aesthetic preservation, such as nacreous iridescence.
• Provenance from Russia, a region well known for rare and high-quality Jurassic ammonites.

Key Features

• Species: Lunuloceras lunula
• Geological Age: Lower Callovian, Middle Jurassic (165 – 163 million years old)
• Provenance: Russia
• Family: Cosmoceratidae, Order Ammonitida
• Distinctive ribbed, evolute shell structure
• Rare nacreous iridescence with natural rainbow-like colours
• Supplied with a Certificate of Authenticity
• Exact specimen pictured is the one you will receive

This fossil is a rare opportunity to acquire an authentic Lunuloceras lunula iridescent ammonite, combining scientific relevance with extraordinary natural beauty.