25090000

Chalk.

2510

Natural calcium phosphates, natural aluminium calcium phosphates and phosphatic chalk.

251010

 Unground:

25101010

Apatite

25101090

Other

251020

 Ground:

25102010

Apatite

25102090

Other

2511

Natural barium sulphate (barytes); natural barium carbonate (witherite), whether or not calcined, other than barium oxide of heading 28.16.

25111000

 Natural barium sulphate (barytes)

25112000

 Natural barium carbonate (witherite)

25120000

Siliceous fossil meals (for example, kieselguhr, tripolite and diatomite) and similar siliceous earths, whether or not calcined, of an apparent specific gravity of 1 or less.