This rock represents the initial stage in the modification of plant material to lignite and bituminous coal. Peat is dark brown to black in color and contains about 50 percent carbon, as well as a great deal of volatile material. It is crumbly and easily broken in the hand.

TEXTURE There are many plant fragments visible in peat, often including large roots. It is frequently high in water and breaks unevenly when dry. Peat is a soft rock.

ORIGIN Forms from the deposition of plant debris on forest floors, in fens, or on moorland. Much of the vegetable matter in the peat that accumulates today is mosses, rushes, and sedges. The deposits may be many feet thick. By decay and reconstruction, the bottom layers of peat banks become compacted, darkened, and hardened, while the carbon content increases.

Grain size: Medium, Fine

Classification: Organic

Fossils: Plants, Invertebrates

Grain shape: None