Carbon the very large masses of carbonate rock (limestone, dolomite, marble and so on). Coal is very rich in carbon (anthracite contains 92–98%) and is the largest commercial source of mineral carbon, accounting for 4,000 gigatonnes or 80% of fossil fuel. As for individual carbon allotropes, graphite is found in large quantities in the United States (mostly in New York and Texas), Russia, Mexico, Greenland, and India. Natural diamonds occur in the rock kimberlite, found in ancient volcanic "necks", or "pipes". Most diamond deposits are in Africa, notably in South Africa, Namibia, Botswana, the Republic of the Congo, and Sierra Leone.
Coal mining in the United Kingdom at ordinary combustion temperatures (i.e. for the oxidation of carbon - see fossil fuels). The last deep coal mine in the UK closed on 18 December 2015. Twenty-six open cast mines still remain open and Banks Mining said in 2018 they planned to start mining a new site in County Durham. The United Kingdom's onshore coal resources occur in rocks of the Carboniferous age, some of which extend under the North Sea. The carbon content of the bituminous coal present in most of the coalfields is 86% to 88%. Britain's coalfields are associated with Northumberland and Durham, North and South