Know all about Coal and Troctolite properties here. All properties of rocks are important as they define the type of rock and its application. Coal belongs to Sedimentary Rocks while Troctolite belongs to Igneous Rocks.Texture of Coal is Amorphous, Glassy whereas that of Troctolite is Phaneritic. Coal appears Veined or Pebbled and Troctolite appears Veined and Shiny. The luster of Coal is dull to vitreous to submetallic while that of Troctolite is not available. Coal is available in black, brown, dark brown, grey, light to dark grey colors whereas Troctolite is available in dark grey to black colors. The commercial uses of Coal are alumina refineries, electricity generation, liquid fuel, manufacture of soap, solvents, dyes, plastics and fibres, paper industry and that of Troctolite are cemetery markers, commemorative tablets, laboratory bench tops, jewelry, sea defence, tombstones.