Molluscs are a hugely varied group of animals, ranging from tiny snails to giant ocean clams. But one thing a lot of them have in common is the ability to grow their own natural armour – a shell.
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These shells are built from a mix of calcium carbonate and a tough protein called conchiolin, and they grow right along with the animal.
Each one is uniquely designed to suit the creature’s habitat and way of life, and therefore come in an incredible range of shapes, patterns and colours. Here we take a closer look at the most uncommon in the world.
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10 rarest shells in the world
Queen conch (Aliger gigas)
The queen conch is one of the Caribbean’s most iconic sea creatures, instantly recognisable by its large, spiraled shell with a glossy pink interior. The snail is prized for its meat, and is commercially threatened in many areas. In places such as Florida, it’s now illegal to collect them, giving populations a chance to bounce back.
Junonia (Scaphella junonia)
The junonia shell typically appears creamy white, scattered with brown spots that help it blend seamlessly into the sandy seafloor. The sea snail itself is bright yellow, decorated with tiny black markings that echo the shell’s design. When the snail dies, the currents of the tropical Western Atlantic wash the empty shells onto the shore, where they are highly coveted by collectors.
Wentletrap (Epitonium scalare)
This small but striking sea snail is known for its elegant, spiral-shaped shell. Its name comes from the Dutch word wenteltrap, meaning 'winding staircase'. It was once considered one of the rarest shells in the world, but today they are typically found in shallow waters around coral reefs in the Indo-Pacific region and the Caribbean.
Glory of the seas cone (Conus gloriamaris)
This striking sea snail, measuring up to 13cm in length, has a golden-brown shell and intricate pattern. For much of the 19th and 20th centuries, it was considered the rarest and most valuable shell in the world – fewer than 100 were known to exist. That all changed in 1969, when divers discovered its natural habitat on sandy sea beds near the Philippines and Indonesia.
Venus comb murex (Murex pecten)
The Venus comb murex is a visually stunning sea snail with a long and slender shell covered in delicate, comb-like spines that are thought to serve as camouflage and protection from predators. It’s found primarily in the Indo-Pacific region, especially around the Philippines, but to find one intact is difficult.
Fulton's cowrie (Cypraea fultoni)
Although cowrie shells are generally common, a few species, such as Cypraea fultoni (pictured) and Cypraea leucodon, stand out for their rarity. They have polished, glossy shells and are found only in limited, remote areas. The snails that produce them live in deep, offshore waters.
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Imperial volute (Cymbiola imperialis)
This intriguing marine mollusc is found in the sandy shallows of the Philippines. It has brown markings on a creamy background, with a flared, glossy orange lip giving it a regal appearance. It is considered uncommon as it’s rarely found in pristine condition.
Sundial shell (Architectonica spp.)
This group of marine gastropods (sea snails) are instantly recognisable due to their flat, spiral-patterned shells, which resemble a sundial. They inhabit tropical and subtropical marine environments, usually found on sandy or muddy sea floors at varying depths.
Rumphius' slit Shell
This whopper of a shell comes from the Pleurotomariidae family, which has has existed for hundreds of millions of years. It's grown by a deep-sea snail, which lives up to 300m deep and can grow up to 2.8m wide. It has a broad cone shape with a rounded base.
Greater argonaut
The argonaut shell isn't actually a shell at all, but the paper thin casing that a female argonaut (a type of pelagic octopus) creates to protect her eggs. These translucent, spiral shells are incredibly fragile and often break before reaching shore, making intact specimens rare.
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Top image: Getty Images