Lignite is a soft, brownish-black type of coal that forms when ancient plant material gets buried, compressed, and heated underground for millions of years. It's the youngest and softest form of coal, sometimes called brown coal because it still looks somewhat like the wood and plants it came from.

When you dig up lignite, it might still show tree bark patterns or plant structures, unlike the hard, shiny black coal you might picture. It crumbles easily in your hands and feels lighter than harder coals. Lignite contains more moisture and produces less heat when burned than older, harder coals like bituminous coal or anthracite.

Power plants in some parts of the world burn lignite to generate electricity, though it creates more smoke and pollution than harder coals. Germany and parts of the United States have large lignite deposits. Miners extract it from open-pit mines rather than deep underground tunnels since lignite deposits sit relatively close to the surface.

Think of lignite as coal that's still partway through its transformation: with millions more years of pressure and heat, it would eventually become harder, shinier, and more energy-rich coal.