Thousands of fortune hunters have started a diamond rush in southern India for rough gems lying on the bed of a river long associated with the stone. The gravel deposits of the Khrishna River in Andhra Pradesh are famous for producing some of the world's best known diamonds, including the legendary 186-carat Kohinoor. Despite India being the world's sole source of diamonds until the 18th century, when Brazilian diamond fields were discovered, there is still no commercial exploitation of this river bed or nearby diamond fields. Instead, whenever word goes around of a diamond digger chancing upon a valuable stone, prospectors descend on villages along the banks of the river and set up camp. This month, news that a 25-carat stone had been found and sold for more than one million rupees (HK$160,000) spread like wildfire. Suddenly, Paritala village was over-run. The diggers are mainly poor farmers whose crops have failed. Other intruders are big-city jewellers who stand on the banks waiting to buy. Everyone is crammed into schools, community halls and homes, where enterprising owners are charging hefty rents. Some villagers, though, are fed up, such as housewives exhausted from cooking meals for hopeful relatives. Stories doing the rounds tell of diggers selling diamonds worth nearly US$48,000 (HK$374,000) in a week. One woman apparently received US$14,500 for a single stone. Some diamond merchants have even hired 'professional' diggers and geologists in the hope of making a killing. By the time a sleepy police and district administration woke up to the invasion, it was a struggle to control crowds. A local journalist said police had to arrest a few hundred diggers and order them to leave in a bid to end the 'madness'. The digging is illegal. The Andhra Pradesh government has passed a law saying that any find has to be reported to the police or government officials, but it is ignored. Aghast at seeing its wealth plundered, the National Mineral Development Corporation has repeatedly warned people against digging, but all in vain. The fantasy of finding another Kohinoor spurs the frenzy. Discovered at a farm in Paritala, the priceless diamond passed through the hands of many a fabled ruler until it was placed in the crown worn by Britain's Queen Victoria. It was seen by millions of TV viewers across the world when the same crown was placed on the Queen Mother's coffin during her funeral in April.