BEIJING (AFP) - A massive deposit of jade weighing about 600 tonnes has been found in north-east China, state media said Friday, with local officials describing the rock as priceless.

The government in Liaoning Province said miners discovered the deposit while digging in a cave in Kuandian Man Autonomous County last year, the official Xinhua news agency reported.

Jade holds mystical properties in China, where it is believed to ward off evil spirits and bring better health.

Wang Xingdong, general manager of the local mining company that found the deposit, said it was priceless, according to Xinhua.

There is no international pricing system for jade. Seen as a classier status symbol than gold, values have been increasing since 2005 as the newly-rich in China have bought up jade products.

Wang said that, given the difficulty of digging the rock out in one piece, there is no plan yet to excavate it.