MRI scans show evidence of an ‘exciting round object’ within the ancient shell which is around ten times the size of its modern counterparts.
The oyster was found in the Solent and given to the Blue Reef Aquarium in Portsmouth, mailonline reported.
“It was discovered in the nets of a fishing boat which was dredging here in the Solent,” said a spokesman from the Blue Reef Aquarium where experts could date it by studying its growth rings.
The aquarium has decided not to explore the evidence because it would destroy the ancient mollusk which is seven inches wide and three inches thick.
A shell of this size can conceal a pearl the size of a golf ball, which would be worth thousands and thousands of pounds.
“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,” explained the Blue Reef Aquarium spokesman.