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 (from the Old English term col, which has meant mineral of fossilized carbon since the 13th century) is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams.oal is extracted from the ground by coal mining, either underground by shaft mining, or at ground level by open pit mining extraction. Since 1983 the world top coal producer has been China. In 2011 China produced 3,520 million tonnes of coal â 49.5% of 7,695 million tonnes world coal production.