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Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements , chiefly hydrogen , sulfur , oxygen , and nitrogen . [ 1 ]
Bituminous coal. Bituminous coal, or black coal, is a type of coal containing a tar-like substance called bitumen or asphalt. Its coloration can be black or sometimes dark brown; often there are well-defined bands of bright and dull material within the seams. It is typically hard but friable.
The following is a list of rock types recognized by geologists.There is no agreed number of specific types of rock. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe a rock type.
An anthracite pile in Trevorton, Pennsylvania. Anthracite derives from the Greek anthrakítēs (ἀνθρακίτης), literally "coal-like". [9] Other terms which refer to anthracite are black coal, hard coal, stone coal, [10] [11] dark coal, coffee coal, blind coal (in Scotland), [7] Kilkenny coal (in Ireland), [10] crow coal or craw coal, and black diamond.
A petrographic microscope is a type of optical microscope used to identify rocks and minerals in thin sections. The microscope is used in optical mineralogy and petrography, a branch of petrology which focuses on detailed descriptions of rocks. The method includes aspects of polarized light microscopy (PLM).
Pennine Coal Measures Group, Pennine coal-bearing succession of rock strata in the United Kingdom; Warwickshire Coalfield, Lower and Middle Coal Measures principal coal seams (in stratigraphic order i.e. youngest/uppermost first) Coal Measures Group, the coal-bearing succession of rock strata which occur in the United Kingdom
Coal Rock) is a prominent nunatak lying 4 nautical miles (7 km) southeast of Fierle Peak at the south end of the Forrestal Range, Pensacola MountainsIt was mapped by the United States Geological Survey (USGS) from surveys and from U.S. Navy air photos, 1956–1966, and named by Dwight L. Schmidt, USGS geologist for two beds of graphitic coal that are well exposed on the nunatak.
Lignite (derived from Latin lignum meaning 'wood'), often referred to as brown coal, [1] is a soft, brown, combustible sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35% [ 1 ] [ 2 ] and is considered the lowest rank of coal due to its relatively low heat content .