Lignite, also called brown coal, is a low-quality coal. Lignite contains 20 to 60 percent water when mined, much more than coal of higher quality. When burned, lignite produces only about half as much heat as other coals. In the United States, it is produced in Montana, North Dakota, and Texas, and is used locally. See also Coal (Coal rank) (Coal as a fuel) (How coal was formed) .
