A naturally occurring dark brown to black combustible rock. Coal is found in nearly every region of the world; it is mined in Europe, Asia, Australia, and North America. Coal is composed of carbonized vegetable matter with small amount of hydrogen, nitrogen, oxygen, and sulfur. Coal is classified by its carbon content. Peat, the first stage in coal formation, is an unconsolidated deposit of semicarbonized plant matter. Lignite, or brown coal, is the lowest rank of coal. It is a consolidated mass with a carbon content of less than 70%. The next level is bituminous, or soft coal. The highest metamorphic rank for coal is anthracite. It has a fixed carbon content between 92 and 98%. It is hard, black and has a semimetallic luster. Coal is primarily used as a fuel. It may have been used as a black pigment in oils and watercolor paints in the early 17th century.
Synonyms and Related Terms
peat; lignite; brown coal; bitumen; soft coal; anthracite; hard coal; trækul (Dan.); Kohle (Deut.); carbón (Esp.); charbon (Fr.); houille (Fr.); carbone (It.); steenkool (Ned.); kull (Nor.); carvão (Port.);
|Density||range from 1.2-1.8|
Hazards and Safety
Dust is toxic by inhalation.
° J.Winter, "The Characterization of Pigments Based on Carbon" Studies in Conservation, 28:49-66, 1983.
Sources Checked for Data in Record
- Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
- Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
- CRC Handbook of Chemistry and Physics, Robert Weast (ed.), CRC Press, Boca Raton, Florida, v. 61, 1980 Comment: density for bintuminous coals=1.2-1.5; for anthracite coals=1.4-1.8
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 201
- Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
- R.D. Harley, Artists' Pigments c. 1600-1835, Butterworth Scientific, London, 1982
- Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000