Color
Black or brown, varying shades
Texture
Can be smooth, granular, or banded
Hardness
Soft to hard, depending on coal type
Luster
Dull to shiny
Density
Varies depending on coal type, typically around 1.2-1.5 g/cm�³
Porosity
Varies, can be porous
Composition
Mainly composed of carbon, along with hydrogen, sulfur, oxygen, and trace minerals
Moisture Content
Can range from a few percent to over 30%
Volatile Matter
Varies, typically 20-45%
Fixed Carbon
Varies, typically 40-90%
Ash Content
Varies, typically 3-30%
Heating Value (BTU/lb)
Varies depending on coal type, typically 8,000-14,000 BTU/lb
Heating Value (MJ/kg)
Varies depending on coal type, typically 24-33 MJ/kg
Combustion Characteristics
Burns to release heat, producing carbon dioxide and other gases