Ancient oyster may hold world’s biggest pearl

An MRI scan of one of the world’s biggest oysters has revealed “compelling evidence” of an 'exciting round object' within the giant shell, reports the Daily Mail.

The oyster, discovered by fishermen in the United Kingdom and given to the Blue Reef Aquarium in Portsmouth, is about ten times the size of a modern mollusk.

Scientists at the aquarium used growth rings to determine the age of the oyster and estimated that it is at least 145 million years old. The aquarium decided to keep the fossil intact and not open its shell despite the lure of a giant gemstone inside.

The Telegraph newspaper reports that a medical charity Cobalt, which provides scanning services to the National Health Service, heard about the giant oyster and volunteered to give it an ultrasound.

"It's obviously a million-to-one chance that it would contain anything but, if you were to go purely on the dimensions of the shell then you'd be looking at a golf ball-sized pearl,” Lindsay Holloway, an aquarium employee, told the Telegraph.

Pearls form inside oysters when a foreign substance slips inside the shell and irritates the oyster. It’s natural reaction is to coat the intruder with many layers of a smooth substance called “nacre” that hardens into a pearl.