Note: Chlorhexidine may cause staining of the tooth, tooth filling, and dentures or other mouth appliances. Tetracycline use during tooth development phases (from the last half of pregnancy through eight years of age) may cause permanent discoloration (yellow, gray, brown) of teeth.
What is Coal made of? Coal is made from trees or plants that decayed on the ground for millions of years. The remains of various plants and trees then mixed with the other components of the ground and eventually going through several natural processes making them more like solid rocks.
Coal Resources. Coal is a fossil fuel of sedimentary origin that has formed by coalification of vegetation over millions of years. Black coal consists of the higher rank anthracite, bituminous and sub-bituminous coals.The lower rank brown coal is sometimes known as lignite.oal Resources. Coal is a fossil fuel of sedimentary origin that has formed by coalification of vegetation over millions of years. Black coal consists of the higher rank anthracite, bituminous and sub-bituminous coals.