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 bride's family most likely had not met the man and are dependent solely on the portrait for an indication of his means and character. Carol Richardson observes that the unidealised representation would have been a significant novelty and shock at the time, and that, complete with the evident skill of the painter, the verisimilitude would have given the sitter weight and creditability. The panel contains two illusionistic passages; the ring and his right hand appear to project out of the painting, while the minutely described fingers of his right hand seem to lie on a parapet positioned on what would