Goniatite Fossil 150mm — Morocco, Devonian Index Fossil

A goniatite fossil from Morocco, 150mm and 544g, the coiled shell of an extinct marine cephalopod preserved in stone for roughly 390 million years since the Devonian period.

Why are goniatites specifically valuable to geologists, beyond their appeal as fossils? They are what's known as index fossils, species that evolved quickly and spread widely enough that their presence in a rock layer tells scientists roughly when that layer formed. Goniatites are especially useful for this because their lineage moved through recognisable stages relatively fast across a run lasting from the Devonian through to their extinction at the end of the Permian, roughly 139 million years later. Beyond the science, goniatite fossils carry a more recent, informal association with grounding and a sense of connection to the planet's deep history.

A closer look

Goniatites were ammonoid cephalopods, relatives of the modern nautilus and, more distantly, squid and octopus. Their shells were internally divided into gas filled chambers connected by a slender tube called a siphuncle, which let the living animal control its buoyancy and move through the water column. This specimen was recovered from Devonian marine limestone in Morocco, a region whose ancient seabeds preserved marine life in exceptional detail.

• Fossil: Goniatite, ammonoid cephalopod
• Age: Devonian, approximately 390 million years old
• Size: 150mm x 120mm x 25mm
• Weight: 544g
• Origin: Morocco

Living with your goniatite fossil

A piece this size suits a desk, a shelf, or a curated fossil and mineral display where its spiral form and chamber lines can be appreciated closely. A soft, dry cloth is all the care a polished fossil like this needs.

Please note: this is a natural fossil specimen and not a substitute for professional medical advice, diagnosis, or treatment. Keep small pieces away from young children.