Anthracite Cornwall, which was used as a pigment. The term is also used to refer to some Carboniferous rock strata found in both Britain and in the Rhenish hill countries (the Culm Measures). Lastly, it may refer to coal exported from Britain during the 19th century. In American English, "culm" refers to the waste or slack from anthracite mining, mostly dust and small pieces not suitable for use in home furnaces. Anthracite is similar in appearance to the mineraloid jet and is sometimes used as a jet imitation. Anthracite differs from ordinary bituminous coal by its greater hardness (2.75–3 on the
Anthracite iron not keep the furnace in operation for more than two months. While distinguished visitors, including Governor Joseph Ritner, acknowledged his success, he sold out his share in Valley Furnace and went to New York City. The research was proceeding along parallel lines across the Atlantic. George Crane, owner, and David Thomas, superintendent of the Yniscedwyn Iron Works, had themselves conceived of the idea of using hot blast to smelt anthracite. Thomas was sent to Scotland to examine Neilson's installation and reproduced it at Yniscedwyn. Crane filed for a British patent on smelting iron with anthracite and hot blast in 1836