It has been said that they're a girl's best friend, they are forever, and they're the hardest substance in the world.

In nature, they're created deep beneath the earth at extreme temperatures and pressure,

yet in the laboratory they can be created in a near vacuum. For all practical purposes you can't

scratch it, yet you can cut it. And economists have noted the paradox of how its price compared

to water. Learn more about diamonds, how they're made and how they're used on this episode of Everything Everywhere Daily. Before I go into the history of diamonds I should start with the physics and

chemistry of diamonds. As you probably know, diamonds are made out of carbon.

That's it, just carbon. With four electrons in its valence shell, there are a lot of ways that carbon can bond with other atoms.

It is why the chemistry of carbon, aka organic chemistry, has so many different carbon-based molecules.

When carbon binds to itself, however, there's has so many different carbon-based molecules.

When carbon binds to itself, however,

there's only a few ways that it can do it.

Those ways, however, can result in materials

with remarkable properties.

The most common form of carbon is graphite. This is a two-dimensional

allotrope of carbon where the carbon atoms are aligned in a single sheet. A single

one of those sheets is known as graphein and when the sheets are found in stacks, it's known as graphite.

Many of the other allotropes of carbon are just different forms of grapheme where the sheets are

turned onto itself to form cylinders or spheres.

Under much higher temperatures and

pressures carbon atoms can align in other ways. In particular, for the purposes of

this episode, carbon atoms can align in a 3D crystal lattice to form diamonds. The naturally occurring diamonds

found on Earth were all probably created over a billion years ago at depths of at least 150

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