Single Ammonite

Quick Answer: The Single Ammonite is one ammonite fossil specimen: the preserved coiled shell of an extinct marine cephalopod related to today’s nautilus, squid and octopus. It is used in biology, geology and earth science lessons on evolution, fossilisation and how rocks are dated.

The Animal Behind the Ammonite

Ammonites were shelled cephalopods that swam in the seas from the Devonian period until the mass extinction at the end of the Cretaceous, about 66 million years ago. The animal lived in the last and largest chamber of its coiled shell; the older chambers behind it were sealed off by walls called septa and connected by a tube, the siphuncle, that let the animal adjust its buoyancy much as a nautilus does today.

Where the septa met the outer shell they left suture lines, and in ammonites these lines are folded into intricate, frilly patterns. On many specimens they show clearly as wavy lines across the surface and are one of the features students can use to tell an ammonite from a nautilus, whose sutures are simple curves.

A single specimen gives every student an object to hold, sketch and describe. The listing does not state the specimen’s size, species, geological age, place of origin or whether it is whole, split or polished, so these details should be settled with the supplier.

How Teachers Use an Ammonite Fossil

• Introducing fossils and the ways shells are preserved as replacements, moulds and casts
• Explaining index fossils and relative dating of rock layers
• Evolution and extinction lessons, including the end-Cretaceous mass extinction
• Comparing ancient and living cephalopods such as the nautilus and squid
• Building a rock and fossil display with specimens from the rocks and minerals range

Specifications

Handling Fossil Specimens

• Hold the ammonite fossil over a table or tray, since dropped specimens chip along the ribs and chamber walls.
• Clean with a soft, dry brush; avoid soaking, acids and household cleaners.
• Keep it dry. Fossils preserved in iron pyrite can slowly crumble in humid air, a process known as pyrite decay.
• Store it in a padded box or tray with a label for its name and, if known, age and locality.

Why Choose LabEquip

Schools, geology departments and science clubs buy single ammonites so that students can handle and describe a fossil themselves. LabEquip supplies the specimen from its biology lab products range, with botany fossil slides available for microscope work; ask through the contact page about size and finish.

Frequently Asked Questions

How old are ammonite fossils?

Ammonites lived from the Devonian period, around 400 million years ago, until the end of the Cretaceous about 66 million years ago. Any single specimen comes from a narrower time span that depends on its species and the rock it came from.

Why are ammonites used as index fossils?

Many ammonite species evolved quickly, lasted only a short time and spread widely across the oceans. Finding the same species in rocks in different places shows that those rock layers formed at about the same time, which is the basis of relative dating.

How can I tell an ammonite from a nautilus?

Look at the suture lines where the chamber walls meet the shell. In ammonites they are folded into complex, frilly patterns; in the nautilus they are simple curves. The siphuncle also runs along the outer edge of the whorl in most ammonites but through the middle of the chambers in the nautilus.

How did the shell become a fossil?

After the animal died, its shell settled on the sea floor and was buried in mud or sand. Over time, minerals such as calcite or pyrite replaced the original shell or filled its chambers, or the shell dissolved and left a mould that later filled to form a cast.

Where are ammonites found in India?

Well-known Indian occurrences include the Jurassic rocks of Kutch in Gujarat and the Spiti valley in Himachal Pradesh, and the shaligram stones collected from the Gandaki river in Nepal are also ammonites. The locality of this specimen is not stated in the listing.

Is the ammonite a natural fossil or a replica?

The product is listed as a single ammonite specimen, but the listing does not describe its preparation. Ask at enquiry whether it is a natural fossil, whether it has been cut and polished, and its approximate size, so it suits the display or handling activity you have in mind.

Last Updated: September 2026