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** How Are Diamonds Made? **

Dave Mosher, Life's Little Mysteries Contributor
Date: 13 November 2012 Time: 10:03 AM ET

diamonds, formation
Diamonds are made by a few steps in Nature including high temperatures and
CREDIT: Diamonds image via Shutterstock

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Diamonds are made out of carbon — highly organized carbon, that is.
Geologists are still guessing how diamonds formed in the Earth from 1
billion to 3 billion years ago, according to a recent study in the journal
/Nature/, but they think the recipe follows something like this:

1. Bury carbon dioxide 100 miles into Earth.

2. Heat to about 2,200 degrees Fahrenheit.

3. Squeeze under pressure of 725,000 pounds per square inch.

4. Quickly rush towards Earth’s surface to cool.

If the process sounds a little difficult, thank a synthetic diamond
manufacturer: There are now two ways to make diamonds in the laboratory.

The first synthetic method is called high pressure, high temperature (HPHT
for short). It’s the closest thing to the diamond-producing bowels of the
Earth, subjecting graphite (yes, the stuff in a No. 2 pencil, which is made
from pure carbon) to intense pressure and heat. Tiny anvils in an HPHT
machine squeeze down on the graphite as intense electricity zaps it,
producing a gem-quality diamond in just a few days. These diamonds,
however, aren’t as pure as natural diamonds because a


how are diamonds made

Diamond - Wikipedia, the free encyclopedia


** Diamond **

From Wikipedia, the free encyclopedia
Jump to: navigation, search
This article is about the mineral. For the gemstone, see Diamond
(gemstone). For other uses, including the shape ◊, see Diamond
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A clear octahedral stone protrudes from a black rock.
The slightly misshapen octahedral shape of this rough diamond crystal in
matrix is typical of the mineral. Its lustrous faces also indicate that
this crystal is from a primary deposit.
Category Native Minerals
(repeating unit) C
Strunz classification 01.CB.10a
Formula mass 12.01 g⋅mol^−1
Color Typically yellow, brown or gray to colorless. Less often blue, green,
black, translucent white, pink, violet, orange, purple and red.
Crystal habit Octahedral
Crystal system Isometric-Hexoctahedral (Cubic)
Cleavage 111 (perfect in four directions)
Fracture Conchoidal (shell-like)
Mohs scale hardness 10
Luster Adamantine
Streak Colorless
Diaphaneity Transparent to subtransparent to translucent
Specific gravity 3.52±0.01
Density 3.5–3.53 g/cm^3
Polish luster Adamantine
Optical properties Isotropic
Refractive index 2.418 (at 500 nm)
Birefringence None
Pleochroism None
Dispersion 0.044
Melting point Pressure dependent
References ^[1]^[2]

In mineralogy, *diamond* (from the ancient Greek αδάμας
– /adámas/ "unbreakable") is a metastable allotrope of carbon,
where the carbon atoms are arranged in a variation of the face-centered
cubic crystal structure called a diamond lattice. Diamond is less stable
than graphite, but the conversion rate from diamond to graphite is
negligible at ambient conditions. Diamond is renowned as a material with
superlative physical qualities, most of which originate from the strong
covalent bonding between its atoms. In particular, diamond has the highest
hardness and thermal conductivity of any bulk material. Those properties
determine the major industrial application of diamond in cutting and


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