This giant pearl could be the biggest ever found in the world and five times larger than the previous record – after being handed in by a fisherman.

The man, who has not been identified, found the priceless 34kg gem ten years ago in sea off the coast of Palawan Island, Philippines.

He didn’t know the potential eye-watering value of $100 million and kept it as a ‘good luck charm’ in his rundown wooden home.

The un-named fisherman discovered this two-foot-long pearl which weighs 34kg and could be worth as much as $100 million after it was discovered off the coast of the  Palawan Island, Philippines inside a giant claim more than a decade ago

But a fire at the property earlier this year forced him to have a clear out and move house.

The fisherman handed it in to the stunned local tourism officer in remote Puerto Princesca who verified that it had been found in a giant clam.

The priceless rock measures a staggering 1ft foot wide and 2.2 feet long – dwarfing the current world’s biggest Pearl of Allah which weighed 6.4kg and is worth $35million.

Tourism officer Aileen Cynthia Amurao said: ‘The fisherman threw the anchor down and it got stuck on a rock during a storm.

‘He noticed that it was lodged on a shell and swam down to pull up the anchor, and also brought the shell with him. This was a decade ago and he kept it at home.

‘He didn’t know how much it was worth and kept it tucked away at home as a simple good luck charm.

‘We were amazed when he brought it to us. We now need help from gemologists to fully certify it. We’re waiting for authentication from Gemologist Institute and other international authorities.

‘But we believe Puerto Princesca is likely earn another prestigious title and a record breaker for having the world’s biggest natural giant pearl from a giant clam.

The fisherman made his discovery off the coast of Palawan Island in the Philippines some ten years ago, file photo

‘We will keep this here in the Philippines and I hope it will bring more tourists to the city.’

The gem was shown off to the public today.

The current record holder is Pearl of Allah, also know as the Pearl of Lao Tze, which was also found off Palawan, Philippines, in 1934. It is on exhibition at the Ripley’s Believe It or Not! in New York.

Clams very rarely create pearls, making the discovery of this gem off Palawan Island extremely rare. Most are made by oysters, but even then they occur in fewer than one in every 10,000 cases.

Giant clams – such as the one that produced this pearl -can reach four feet in length and weigh upwards of 500 pounds.

Natural pearls are formed inside the shells of molluscs as a defence mechanism against a potentially threatening irritant, such as a parasite. Despite popular belief, pearls rarely grow from a grain of sand.

The animal creates a pearl sac and secretes calcium carbonate to seal off the irritation. This secretion process is repeated many times, producing a pearl.

The jewel increases in size as each new layer of calcium carbonate is deposited. Saltwater pearls usually take two to three years to develop, but larger pearls such as the one held in Puerto Princesca would have taken far longer.

Searching for wild pearls is relatively safe today, but in the 19th century, the mortality rate for divers was a high as 50 per cent. They faced attacks from sharks, as well as the crippling affects of decompression sickness, known as the bends.

Source: The National Geographic