Image caption China provides 97% of the world's supply of rare earth minerals

China has said it will cut exports of rare earth minerals by 10% in 2011.

World manufacturers are heavily reliant on China for these minerals, which are essential for making many electronic goods, such as TVs and PC monitors.

China provides 97% of the world's supply of these minerals. The US mined none last year.

Rare earth minerals have been a thorny trade topic for some time, and China has previously promised not to cut supplies drastically.

Rare earths are a collection of seventeen chemical elements in the periodic table: scandium, yttrium, and some fifteen lanthanides.

Shares in two Australian companies, which are planning to mine rare earths, jumped more than 10% on the news.

Australia's Lynas Corp , which owns the richest known deposit of rare earth outside China, rose 10.8% while its rival Arafura rose 11.1%.

The US last week said it was "very concerned about China's export restraints on rare earth materials, antimony and tungsten" and could still file a case on that at the World Trade Organisation.

In September, China blocked exports of rare earths to Japan after a territorial row but later resumed them.

The US does have some rare earth supplies and is hoping to start production.

What are rare earths? Despite their name, rare earths are not particularly rare

The term refers to 17 elements, most of which are fairly abundant in nature

Rare earths are a collection of seventeen chemical elements in the periodic table: scandium, yttrium, and some fifteen lanthanides

Some are as common as copper or zinc, while even the rarest occur in greater quantities than gold or platinum

They are essential in the manufacture of many electronic goods Concern over rare earths shortage Japan seeks rare earths options

Their uses also include the manufacture of wind turbines and hybrid cars.

Growing demand

China has been reducing export quotas of rare earths over the past several years to cope with growing demand at home.

A Commerce Ministry spokesman has also said that China is cutting its supply side too, reining in exploration, production and exports because of what it says are environmental concerns.

The country also plans to raise duties on some rare earths and set up a trade association of suppliers.

China usually issues a second batch of quotas during the year, and it is not known how the figures will change later in 2011.

Japanese manufacturer Sony said Beijing's move was a hindrance to free trade - adding it would work to reduce its reliance on the minerals.

The firm said it was crucial to producing items including magnets, condensers, and abrasives for polishing glass on LCD screens.