sedimentary
Coal (Bituminous or Anthracite)
Carbonaceous Sedimentary Rock
Mohs hardness of 1.0 to 2.5; dark brown to pitch black color; vitreous, sub-metallic, or dull luster; non-crystalline amorphous structure; brittle with conchoidal to uneven fracture; specific gravity ranges from 1.1 to 1.4.
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Physical properties
Mohs hardness of 1.0 to 2.5; dark brown to pitch black color; vitreous, sub-metallic, or dull luster; non-crystalline amorphous structure; brittle with conchoidal to uneven fracture; specific gravity ranges from 1.1 to 1.4.
Formation & geological history
Formed over tens to hundreds of millions of years through the decay and compaction of dead plant matter in swampy, oxygen-poor environments under high heat and pressure deep underground.
Uses & applications
Primarily burned for electricity generation and heating, used in steelmaking (coking coal), and utilized in chemical production for plastics, synthetic fibers, and fertilizers.
Geological facts
Coal is an organic sedimentary rock composed mainly of carbon, along with variable amounts of other elements like hydrogen, sulfur, oxygen, and nitrogen. It accounts for a significant portion of global energy production.
Field identification & locations
Identified by its lightweight feel compared to normal rocks, dark black color, and tendency to smudge hands or leave a dark streak. Commonly found in sedimentary basins and mining regions globally.
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