sedimentary
Coal
Biogenic sedimentary rock (Carbon)
Hardness ranges from 1 to 3 on the Mohs scale depending on the rank; color is black or brownish-black; luster ranges from dull to vitreous or sub-metallic; amorphous crystal structure with no cleavage; low specific gravity around 1.3 to 1.4.
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Physical properties
Hardness ranges from 1 to 3 on the Mohs scale depending on the rank; color is black or brownish-black; luster ranges from dull to vitreous or sub-metallic; amorphous crystal structure with no cleavage; low specific gravity around 1.3 to 1.4.
Formation & geological history
Formed from the remains of ancient swamp vegetation buried in aquatic environments under high heat and pressure over millions of years (Carboniferous period and onward).
Uses & applications
Primary used for electricity generation, steel production, and industrial manufacturing.
Geological facts
Coal is often called bottled sunshine because the energy it stores originates from sunlight captured by plants millions of years ago.
Field identification & locations
Easily identified by its light weight, dark black color, and the dark streak it leaves on porcelain plate; commonly found in sedimentary basins worldwide.
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