Know all about Coal and Tephrite properties here. All properties of rocks are important as they define the type of rock and its application. Coal belongs to Sedimentary Rocks while Tephrite belongs to Igneous Rocks.Texture of Coal is Amorphous, Glassy whereas that of Tephrite is Aphanitic to Porphyritic. Coal appears Veined or Pebbled and Tephrite appears Vesicular. The luster of Coal is dull to vitreous to submetallic while that of Tephrite is subvitreous to dull. Coal is available in black, brown, dark brown, grey, light to dark grey colors whereas Tephrite is available in black, brown, colourless, green, grey, white 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 Tephrite are production of lime, soil conditioner.