Anthracite

n. coal which burns with little smoke or flame

Anthracite (Greek Ανθρακίτης, literally "a form of coal", from Anthrax [Άνθραξ], coal) is a hard, compact variety of mineral coal that has a high luster. It has the highest carbon count and contains the fewest impurities of all coals, despite its lower calorific content. Anthracite coal is the highest of the metamorphic rank, in which the carbon content is between 92 nd 98%. The term is applied to those varieties of coal which do not give off tarry or other hydrocarbon vapours when heated below their point of ignition. Anthracite ignites with difficulty and burns with a short, blue, and smokeless flame.
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Noun
1. a hard natural coal that burns slowly and gives intense heat
(synonym) anthracite coal, hard coal
(hypernym) coal

adj. grey, of the color grey

n. anthracite, coal which burns with little smoke or flame

(n.)
A hard, compact variety of mineral coal, of high luster, differing from bituminous coal in containing little or no bitumen, in consequence of which it burns with a nearly non luminous flame. The purer specimens consist almost wholly of carbon. Also called glance coal and blind coal.