Brown to brownish-black fossil fuel of low rank, intermediate between peat and lignite. It is soft, with a dull lustre and earthy texture, and contains the remains of plants; has a high moisture content (45–66%), and decomposes and darkens on dehydration. Its ash content is 1–5%, and its calorific value varies from low in soft, high-moisture types to high in those resembling lignites. It comes mainly from east and central Europe, where it is mined from open-cast pits.