Actually diamonds come from coal. Is it true ?
Many people believe that diamonds are formed from metamorphosis from coal. The idea continues to be "how diamonds form" stories in many science classes.
Coal rarely plays a role in diamond formation. In fact, most of the diamonds that have been dated are much older than Earth's first terrestrial plant - coal source material! That alone is enough evidence to close the idea that Earth's diamond deposits are formed from coal.
Another problem with the idea is that coal seams are sedimentary rocks which usually occur as horizontal or almost horizontal rock units. However, rock sources of vertical pipe diamonds are full of igneous rocks.
Coal rarely plays a role in diamond formation. In fact, most of the diamonds that have been dated are much older than Earth's first terrestrial plant - coal source material! That alone is enough evidence to close the idea that Earth's diamond deposits are formed from coal.
Another problem with the idea is that coal seams are sedimentary rocks which usually occur as horizontal or almost horizontal rock units. However, rock sources of vertical pipe diamonds are full of igneous rocks.
Rough Diamond
Four processes are considered responsible for almost all natural Diamonds that have been found at or near the surface of the earth. One of these processes accounts for almost 100% of all Diamonds that have ever been produced from Diamond mines from several countries in the world. The remaining three are significant sources of commercial Diamonds.
The most convincing evidence that coal does not play a role in the formation of most Diamonds is a comparison between the age of Diamonds and the age of early land plants.
Almost every dated Diamond was formed during the Precambrian Eon - the span of time between the formation of the Earth (about 4,600 million years ago) and the beginning of the Cambrian period (around 542 million years ago). In contrast, early land plants did not appear on Earth until around 450 million years ago - nearly 100 million years after the formation of almost all natural Diamonds of the Earth.
Because coal is formed from terrestrial plant remains, and the oldest land plants younger than almost every Diamond that have ever dated, it is easy to conclude that coal does not play an important role in the formation of earth's Diamonds.
The most convincing evidence that coal does not play a role in the formation of most Diamonds is a comparison between the age of Diamonds and the age of early land plants.
Almost every dated Diamond was formed during the Precambrian Eon - the span of time between the formation of the Earth (about 4,600 million years ago) and the beginning of the Cambrian period (around 542 million years ago). In contrast, early land plants did not appear on Earth until around 450 million years ago - nearly 100 million years after the formation of almost all natural Diamonds of the Earth.
Because coal is formed from terrestrial plant remains, and the oldest land plants younger than almost every Diamond that have ever dated, it is easy to conclude that coal does not play an important role in the formation of earth's Diamonds.
Diamond formation process
Diamond Formation on Earth Mantle
Geologists believe that Diamonds throughout Earth's commercial diamond deposits are formed in the mantle and sent to the surface by deep-source volcanic eruptions. This eruption produced kimberlite and lamproite pipes which were sought by diamond prospectors. Weathered and eroded diamonds from these eruption deposits are now contained in sediment (placer) river deposits and coastlines.
Natural diamond formation requires very high temperatures and pressure. This condition occurs in the limited zone of the Earth's mantle about 90 miles (150 kilometers) below the surface where the temperature is at least 2000 degrees Fahrenheit (1050 degrees Celsius). This critical temperature-pressure environment for diamond formation and stability is not present globally. Instead he thought to be present mainly in the mantle under the stable interior of the continental plate.
Diamonds are formed and stored in a "diamond stability zone" which is sent to the earth's surface during deep-source volcanic eruptions. This eruption ripped through the mantle and brought them quickly to the surface. See Location 1 in the diagram at the top of the page. This type of volcanic eruption is very rare and has never happened since scientists have been able to recognize them.
Is coal involved? Coal is sedimentary rock, formed from the remains of plants stored on the surface of the earth. This is rarely buried to a depth of more than two miles (3.2 km). It is highly unlikely that coal has been moved from the crust to a depth below the base of the continental plate. This carbon source of diamond mantle is most likely carbon trapped in the interior of the earth at the time of planet formation.
Geologists believe that Diamonds throughout Earth's commercial diamond deposits are formed in the mantle and sent to the surface by deep-source volcanic eruptions. This eruption produced kimberlite and lamproite pipes which were sought by diamond prospectors. Weathered and eroded diamonds from these eruption deposits are now contained in sediment (placer) river deposits and coastlines.
Natural diamond formation requires very high temperatures and pressure. This condition occurs in the limited zone of the Earth's mantle about 90 miles (150 kilometers) below the surface where the temperature is at least 2000 degrees Fahrenheit (1050 degrees Celsius). This critical temperature-pressure environment for diamond formation and stability is not present globally. Instead he thought to be present mainly in the mantle under the stable interior of the continental plate.
Diamonds are formed and stored in a "diamond stability zone" which is sent to the earth's surface during deep-source volcanic eruptions. This eruption ripped through the mantle and brought them quickly to the surface. See Location 1 in the diagram at the top of the page. This type of volcanic eruption is very rare and has never happened since scientists have been able to recognize them.
Is coal involved? Coal is sedimentary rock, formed from the remains of plants stored on the surface of the earth. This is rarely buried to a depth of more than two miles (3.2 km). It is highly unlikely that coal has been moved from the crust to a depth below the base of the continental plate. This carbon source of diamond mantle is most likely carbon trapped in the interior of the earth at the time of planet formation.
