China has discovered the world's second-largest deposit of light rare earths in Mianning county, Sichuan province, adding 9.67 million metric tons of rare earth oxides to its reserves — an increase of more than 300 percent, the Ministry of Natural Resources announced on Tuesday.

Rare earth oxides are widely used in fields such as magnetic and fluorescent materials, making them indispensable to modern industry and high-end manufacturing.

In addition, newly associated resources were identified in the Maoniuping mining area in Mianning county, including 27.14 million tons of fluorite and 37.23 million tons of barite, both classified as ultra-large deposits.

Fluorite and barite are nonrenewable resources. Fluorite is a key source of industrial fluorine, essential for emerging and future industries. Barite, known for its chemical inertness, resistance to acids and alkalis, high density and radiation absorption properties, is a critical raw material in industries such as petroleum, chemicals, pharmaceuticals and construction.