Prehistoric oyster

This is the fossilised oyster that could contain the one of the largest gem-quality pearls in the world, scientists say.An MRI scan has revealed compelling evidence of an 'exciting round object' within the ancient shell.

The prehistoric oyster, which is around ten times the size of its modern counterparts and thought to be up to 145million years old, was trawled up by fishermen in the Solent and given to the Blue Reef Aquarium in Portsmouth.But the aquarium has decided not to explore the tantalising evidence any further to protect the integrity of the ancient mollusc, which would have to be destroyed to extract its mysterious contents.

A shell of this size could be concealing a pearl the size of a golf ball, dwarfing the average 7mm diametre size of an oyster pearl.Such a gem would be worth thousands and thousands of pounds.The oyster has been given to the Blue Reef Aquarium in Portsmouth, Hampshire, where experts there have managed to date it by studying its growth rings, much like a tree.It was hauled up in the Solent and found in the nets of the trawler boat when it returned to port.



After layers of mud were washed off, it was clear the item was a huge fossilised shell that measured seven inches wide and three inches thick.Following news of its discovery a company in Cheltenham called Cobalt, which provides state of the art scanning services to the NHS and private patients, volunteered to scan the oyster to see what was inside.

A spokesman from the Blue Reef Aquarium said: 'It was discovered in the nets of a fishing boat which was dredging here in the Solent. 'When the fishermen came back to port they thought it was real, but when they picked it up, cleaned it, and had a closer look they could tell it was a fossil. It had completely turned to stone.

'A member of the public called and informed us it was on display at a local fishmongers so we called them and they gave it to us to have in the aquarium.'Oysters can be aged by annual growth rings on their shells and we have counted more than 200 rings on this oyster making it an extremely long-lived individual.'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.'