sedimentary
Lignite (Brown Coal)
Lignite (C189H155O6N3S)
Hardness: 2.0-2.5 (Mohs scale), Color: Brown to black, Luster: Dull to earthy, Crystal Structure: Amorphous, Specific Gravity: 0.5-1.5.
- Hardness
- 2
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Physical properties
Hardness: 2.0-2.5 (Mohs scale), Color: Brown to black, Luster: Dull to earthy, Crystal Structure: Amorphous, Specific Gravity: 0.5-1.5.
Formation & geological history
Formed from naturally compressed peat through the process of coalification at relatively shallow depths and low temperatures (less than 100°C). Typically dates from the Tertiary or Cretaceous periods.
Uses & applications
Primarily used as a fuel for steam-electric power generation; also used in agriculture as a soil conditioner and as a source of montan wax.
Geological facts
Lignite is considered the lowest rank of coal due to its high moisture content and relatively low heat content. It is sometimes called 'brown coal'.
Field identification & locations
Identify by its distinct brown color, crumbly texture, and earthy odor when damp. Often found in proximity to other sedimentary layers like clay and sandstone in basin environments.
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