The opalised moon snail is on one of four new stamps featuring opalised fossils.

The featured fossils are from the early Cretaceous Period, around 100 million years ago.

In addition to the snail, which features in the South Australian Museum fossil collection, the collection includes three other fossils from the collections of the Australian Opal Centre.

The other fossils include an opalised pine cone, an opalised dinosaur tooth and an opalised wood fragment.

The museum's senior collections manager of earth sciences Ben McHenry said the snail fossil was uncovered in an opal mine in Coober Pedy.

READ MORE:

"In life this moon snail (Euspira reflecta) was an active sea-floor predator preying on sessile bivalves such as mussels and cockles," he said.

"Using its file-like teeth, it would drill a hole through the protective bivalve shell and eat its victim from the inside out." .

Moon snails are still alive today and both their shells and egg masses are commonly found along Adelaide's beaches.

The South Australian Museum holds the world's largest public collection of Australian opal and devotes an entire display gallery to its opalised fossils.

READ MORE: Aust Post seeks volunteers to clear mail

The moon snail is on special display in the museum's opal fossils gallery and the stamp packs are available while stocks last.

They are also available at the museum's gift shop, at participating Post Offices, by mail order on 1800-331-794, or by clicking here.