An amateur explorer in Australia has unearthed a gold nugget weighing an astonishing 5.5 kg worth $315,000. The unidentified man, using a handheld metal detector, found the nugget on Wednesday, lying 60 centimetres underground near the town of Ballarat. The value of the nugget has been estimated at more than 300,000 Australian dollars ($315,000), the Herald Sun reported. Ballarat Mining Exchange Gold Shop owner and dealer Cordell Kent said the prospector heard a faint noise on his detector and removed a dense pile of leaf mulch before he started digging.