A massive bentonite deposit with proven reserves of 610 million tons has been discovered in south China's Guangxi Zhuang Autonomous Region, officials said.

The discovery is believed to be the largest in the country and also unusual in the world, said officials with the Guangxi regional bureau of geological exploration and development.

It lies in the middle of Ningming Basin in Ningming county and covers an area of 30 square kilometers. Between 1.3 meters and 3.5 meters in the bed is recoverable.

An absorbent aluminum silicate clay formed from volcanic ash, bentonite is used in various adhesives, cements, and ceramic fillers. A total of 10 million tons of the mineral are consumed annually across the world.

So far, China has 2.4 billion tons of proven bentonite reserves, according to the bureau officials.

(Xinhua News Agency February 11, 2008)