Starting 345,000,000 years ago, swamps formed and sea sediments covered them hundreds of times, making many rock and dead-plant layers. Layer weight created high pressure that changed organic matter into carbon forms {carbon mineral}.
types
Under pressure, organic matter turns slowly into first peat, then lignite, then bituminous coal, and then anthracite coal, as it becomes more crystalline.
coal
Many places that used to be under sea have coal, such as USA, Canada, England, and Russia.
petroleum
Decaying organic matter trapped in anti-clinal deposits became petroleum, with natural gas above it, as in Saudi Arabia, Middle East, and Russia.
diamond
Diamonds are covalently bound pure carbon and form at 5000 F and 1,000,000 lb/in^2 pressure, 240 miles below surface. Almost all diamonds are in South Africa. Diamond size is by weight {carat}.
graphite
Graphite is soft carbon. Hexagon graphite layers include heptagons, resulting in negative curvature. Hexagon graphite layers include pentagons, resulting in positive curvature.
Physical Sciences>Earth Science>Mineral>Kinds>Carbon
5-Earth Science-Mineral-Kinds-Carbon
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Date Modified: 2022.0224