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.
Formed deep underground over thousands of years of heat and pressure, coal is a carbon-rich black rock that releases energy when burned. In the United States, roughly 30 percent of all electricity comes from coal: the rest comes from natural gas, nuclear, and renewables like wind and solar. Most US coal comes from either above-ground mines in Wyoming and Montana, or underground mines in Appalachia.