Coal

Not to be confused with Charcoal

Maramarua Open Cast Coal Mine in New Zealand, 1966

Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Coal is primarily used as a fuel. Coal is very soft ranking from 2 to 4 on the Mohs hardness scale, while sandstone ranks from 5 to 7.

Dependencies

• Carbon
• Peat
  • Coal
  • Fuel

See also

• Raw material
• Activated charcoal
• Carbon dioxide
• Charcoal
• Fire

References

This article uses material from the Wikipedia article Coal, which is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License (view authors).