Chemical composition: C content is 95%, H content is 2.2%, O content is 2%, and N content is 0.8%. It is the coal that contains the most C and the least H, O, and N.

Physical properties: gray black to jet black; black streaks; glass to semi-metallic luster, sometimes grease luster. Hardness 2.5~3; shell-shaped or jagged fracture; does not stain hands. Relative density 1.4~1.7. There is no flame, no odor when burning, and it does not sinter into blocks. The calorific value is 8100 cal/g.

The origin is layered or convex lens-shaped and occurs in the marine and continental sedimentary structures of the Cambrian to Neogene.

The main uses are, depending on the calorific value, used to generate electricity, make gas, nitrogen fertilizer, smelt white iron and use as civil fuel.

Thinking questions and exercises

1) What are organic minerals? What types of organic minerals are there? What are the composition characteristics of organic minerals?

2) What are organic quasi-minerals? What are the main organic quasi-minerals?

3) What are the conditions for the formation of organic minerals and organic quasi-minerals?