Anthracite Mohs scale), its higher relative density of 1.3–1.4, and luster, which is often semi-metallic with a mildly brown reflection. It contains a high percentage of fixed carbon and a low percentage of volatile matter. It is also free from included soft or fibrous notches and does not soil the fingers when rubbed. Anthracitization is the transformation of bituminous coal into anthracite. The moisture content of fresh-mined anthracite generally is less than 15 percent. The heat content of anthracite ranges from 22 to 28 million Btu per short ton (26 to 33 MJ/kg) on a moist, mineral-matter-free basis. The heat content
Portrait of a Man with a Blue Chaperon a fur lined brown jacket over a black undervest. His headdress, a chaperon, contains two wings which hang down over the man's shoulders and extend to his chest. The edges of the cloth are given a shredded look at the edges of their trains. The hood is brightly and dramatically coloured using pigment extracted from the expensive lapis lazuli gemstone to give it its bright, intense hue. The headdress is of a similar but less extravagant type to that seen in van Eyck's c. 1433 "Portrait of a Man", and worn by a figure in the distance in his c.