Organic group can further be divided into coal grains and unburnt carbon, while inorganic group includes cenosphere, magnetic sphere, irregular grains, quartz fragment and mullite, etc.

• 有机组分包括煤粒和残炭2个亚组；而无机组分则可进一步分为玻璃微珠、磁铁微珠、不定形颗粒、碎屑石英和莫来石。