A pearl, believed to be the largest ever found, was hidden under a bed for ten years because its finder had no idea of its value.
At 34kg, the pearl is believed to be the biggest ever discovered. It measures a foot across and 2.2 feet long, and is five times bigger than the current world record holder: a pearl known as the Pearl of Allah which weighs 6.4kg.
And while the Pearl of Allah has been valued at $35 million, this latest discovery is believed to be worth as much as $100 million - or £76 million.
It was discovered by a fisherman, who hasn't been named, off the coast of Palawan Island in the Philippines. He'd dropped his anchor, but realised it was snagged on something that turned out to be a giant clam. The the enormous pearl was found inside.
With no idea of its enormous value, the fisherman kept the pearl under his bed as a good luck charm - and it was only when a fire destroyed his wooden home earlier this year that it came to light.
According to the Palawan News, he has handed it over to the local tourism office for safe keeping, and it was yesterday placed on display at the Puerto Princesa City Hall.
More commonly, beach-combers can find semi-precious or even precious stones. Garnets wash up regularly at Ruby Bay in Scotland, for example, while the coast of Suffolk is famous for its amber.
Meanwhile, fossils - sometimes valuable ones - are to be found on a number of beaches, most notably along Dorset's Jurassic Coast. However, beach-combers are asked not to chip items out from the rocks, but to stick to collecting those that are already exposed.
And while historical finds may be claimed by the Crown, there's no such rule over 'unworked natural objects or minerals as extracted from a natural deposit' - meaning that your find should be yours to keep.