How are Diamonds Made?

sunandaC

Sunanda K. Chavan
Diamonds are used in the National High Magnetic Field Laboratory in the saw blade," Tibbetts said.

"Being the hardest material known, they are used to cut through certain rocks. Also, research is being done regarding Europa â€" one of Jupiter's icy moons, in which certain bacteria may be found in diamonds because they are produced at such high pressures."


How it is maid?
• All diamonds are at least 990,000,000 years old.

Many are 3,200,000,000 years old (3.2 billion years)!!!

How do we know this?

Age: from Carbon dating? NO! C-dating only works for very young carbon.

You need to use other radioactive decay schemes (e.g., uranium-lead) to date inclusions in diamonds. Inclusions used for dating are around 100 microns in diameter (0.1 mm).

• Diamonds are formed deep within the Earth: between 100 km and 200 km below the surface.

Diamonds form under remarkable conditions!

• The temperatures are about 900 - 1300 C in the part of the Earth's mantle where diamonds form.

• The pressure is between 45 - 60 kilo bars. (kB)

 50 kB = 150 km = 90 miles below the surface

 60 kB = 200 km = 120 miles below the surface

• Diamonds are carried to the surface by volcanic eruptions.

The volcanic magma conduit is known as a kimberlite pipe or diamond pipe. We find diamonds as inclusions in the (rather ordinary looking) volcanic rock known as kimberlitic.

NOTE: The kimberlitic magmas that carry diamonds to the surface are often much younger than the diamonds they transport (the kimberlite magma simply acts as a conveyer belt!).

• Diamond is made of carbon (C), yet the stable form (polymorph) of carbon at the Earth's surface is graphite.


• To ensure they are not converted to graphite, diamonds must be transported extremely rapidly to the Earth's surface.It is probable that kimberlite lavas carrying diamonds erupt at between 10 and 30 km/hour (Eggler, 1989). Within the last few kilometers, the eruption velocity probably increases to several hundred km/hr.


• Diamond is the hardest material.Diamond is the hardest gem on the MOHS harness scale and graphite (also made from carbon atoms) is the softest! Given that both diamond and graphite are made of carbon, this may seem surprising.
The explanation is found in the fact that in diamond the carbon atoms are linked together into a three-dimensional network whereas in graphite, the carbon atoms are linked into sheets with very little to hold the sheets together (thus the sheets slide past each other easily, making a very soft material).
 
Diamonds are used in the National High Magnetic Field Laboratory in the saw blade," Tibbetts said.

"Being the hardest material known, they are used to cut through certain rocks. Also, research is being done regarding Europa â€" one of Jupiter's icy moons, in which certain bacteria may be found in diamonds because they are produced at such high pressures."


How it is maid?
• All diamonds are at least 990,000,000 years old.

Many are 3,200,000,000 years old (3.2 billion years)!!!

How do we know this?

Age: from Carbon dating? NO! C-dating only works for very young carbon.

You need to use other radioactive decay schemes (e.g., uranium-lead) to date inclusions in diamonds. Inclusions used for dating are around 100 microns in diameter (0.1 mm).

• Diamonds are formed deep within the Earth: between 100 km and 200 km below the surface.

Diamonds form under remarkable conditions!

• The temperatures are about 900 - 1300 C in the part of the Earth's mantle where diamonds form.

• The pressure is between 45 - 60 kilo bars. (kB)

 50 kB = 150 km = 90 miles below the surface

 60 kB = 200 km = 120 miles below the surface

• Diamonds are carried to the surface by volcanic eruptions.

The volcanic magma conduit is known as a kimberlite pipe or diamond pipe. We find diamonds as inclusions in the (rather ordinary looking) volcanic rock known as kimberlitic.

NOTE: The kimberlitic magmas that carry diamonds to the surface are often much younger than the diamonds they transport (the kimberlite magma simply acts as a conveyer belt!).

• Diamond is made of carbon (C), yet the stable form (polymorph) of carbon at the Earth's surface is graphite.


• To ensure they are not converted to graphite, diamonds must be transported extremely rapidly to the Earth's surface.It is probable that kimberlite lavas carrying diamonds erupt at between 10 and 30 km/hour (Eggler, 1989). Within the last few kilometers, the eruption velocity probably increases to several hundred km/hr.


• Diamond is the hardest material.Diamond is the hardest gem on the MOHS harness scale and graphite (also made from carbon atoms) is the softest! Given that both diamond and graphite are made of carbon, this may seem surprising.
The explanation is found in the fact that in diamond the carbon atoms are linked together into a three-dimensional network whereas in graphite, the carbon atoms are linked into sheets with very little to hold the sheets together (thus the sheets slide past each other easily, making a very soft material).

Very nice topic sunanda! It is really a great information and very happy knowing about the methods of making a diamond. Well sunanda, i am also sharing a presentation which will describe it in more details with some pictures.
 

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