Other forms: peats
Peat is a rich, dark, dirt-like material that's made from decomposed organic matter. You can use peat in gardens and potted plants, to help the soil stay moist.
Peat is like a naturally occurring compost — it forms in bogs from plants that have broken down. In many parts of the world, peat is burned as a fuel, and in others it's a popular mulch in gardens and on farms. If it's left to continue decomposing for many years, peat eventually turns into lignite, a low-grade coal that can also be burned for heat or as an energy source.