Coal
Rock
Common
A black or brownish black rock that burns: mostly carbon, from plants buried as peat and cooked for millions of years. Its ranks run from brown lignite through bituminous coal to hard anthracite as heat and burial increase.
Rock
- Kind of rock
- Organic sedimentary rock
- Rock family
- Sandstone, shale and clay
- Also contains
- Pyrite
- Deposits
- Coal seam
- How it forms
- Dead plants of coal-forest wetlands, shielded from the air by mud and water, turn to peat and then coal under burial; most formed in the late Carboniferous and early Permian.
- Uses
- Fuel: carved as ornaments in Neolithic China, used to smelt copper at Fushun about 1000 BC, dug in every English coalfield by the Romans, and the fuel of the steam engine.
Identity
- Also known as
- Lignite (brown coal), Bituminous coal, Anthracite (hard coal), Seacoal
Crystallography
- Habits
- Massive
Physical properties
- Luster
- Dull, Submetallic
- Colors
- black, brownish black
- Transparency
- Opaque
Geology
- Origins
- Sedimentary
- Geography
- China (Fushun), India, Indonesia, Australia, Russia, England
Classification
- Rarity
- Common
- Gem quality
- No
Sources
- Coal. Wikipedia.
- C. R. Hallsworth, R. W. O’B. Knox, BGS Rock Classification Scheme, Volume 3: Classification of sediments and sedimentary rocks (Research Report RR 99-03). British Geological Survey, 1999.
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