Millions of dollars worth of diamonds have been stolen from a hotel in Monte Carlo, and the reason that people like diamonds is because they sparkle so much here.

I've got a model of a dam and and the diamonds that you see on the diamonds that a stolen are cut with these very precise geometrical faces, which is what makes them sparkle.

And they sparkle so much, much better than this lump of glass.

Because Hammond has a very high refractive index it bends light for is strongly on.

Although people don't realize it, they really value damn and because of its refractive index.

But chemists think about diamond in a completely different way.

They're interested in derm and because of its structure, you can see here I've got a model of diamond.

It's very strong.

I can push hard on here and it will not distort it all.

So if you look at this atom here, it is bonded to four other atoms.

One here, one there 3rd 1 here and forth, one here and each atom is bonded to four others.

So get very strong structure.

Chemists value diamond because it's so strong and they're two different ways.

You can use it to be strong.

One way is is a window to let light in or out of a high pressure vessel.

So here is the diamond window, which is mounted on the plate on the whole thing, fixed to a metal fitting for high pressure work on Dhe.

If you look through the diamond, you can actually see.

I concede Brady's wedding ring can't remember whether it's platinum, I think palladium.

So I can just about see his lens.

Now the idea of this is that you can shine light through a very high pressure fluid and look at the reaction.

The high pressure's not terribly high.

Perhaps 100 atmospheres, 200 atmospheres pressure.

But if you use glass Utah Excuse really thick glass, and that would distort the experiment.

The diamonds that are now used for windows like that they usually synthetic diamonds.

The structure is just the same, but the rial power of diamonds is when you need very high pressures and you do this with the diamond that is tapered like this one.

You can see it goes downwards down here.

And when you have a shape like that, if you press hard on the top because the area of the top is much bigger than the area of the bottom, you increase the force as you push down and multiply, so you get very high pressure at the bottom.

With windows shaped like this, you can get a very high pressure on those tiny face at the bottom, which has a special name.

It's called the Color it face of a diamond so you can take a pair of dams like this one on the top, another one pushing up here and pushed them together.

And this little cell here has two plates.

One here and one here, which have pushed together and pushed the diamonds together on the force, comes from screws that told the plate together.

So if I turn this over, you can see they're three screws, which you can tighten, which forced these together.

The amazing thing with this tiny cell you can squeeze a suitably small sample to pressures of more than 100,000 atmospheres.

This is really high pressures, so the way you use the cell is that you take so small crystal that you want to submit to a high pressure and put it between the diamonds surrounded by a small ring made of tungsten so the liquid will transmit the force from the dam ends onto the crystal because if you just put the crystal between it, it will be crushed to bits.

If it's surrounded by liquid, the pressure pushes from all sides, and all being well, it just gets squeezed.

Some crystals.

It makes no difference if you submit them to pressure, but if you have quite a complicated molecule as you increase the pressure, it can change its structure.

Even the diamonds that are used in labs are quite valuable, and so sometimes even our down mons gets stolen.

But the thieves are usually disappointed because their value on the black market is very small because nobody wants to wear diamonds like this is jewelry.

Originally damn ins were made by heating carbon at very, very high pressure on dhe.

This was expensive, and you got rather poor damn ins.

Modern diamonds are made by so called chemical vapour de position where you take compound in the gas phase at high temperature, and it decomposes to give a layer of carbon, and if you do it in the right conditions, you can build up diamond literally layer by layer.

So if you want, you can coat metals with diamonds.

Or you can grow whole crystals of diamonds rather like the ones here.

Is there a difference between manufactured diamonds and diamonds that come out of the ground?

Manufacture diamonds do not usually have the same high optical quality that makes natural diamonds so beautiful.

Because natural diamonds have bean made under high pressure and sat under the ground for millions of years and the tiny imperfections which didn't really matter.

The scientists have essentially disappeared because the diamond has been heated so long that they can diffuse out.

And so you get these really perfect crystals.

So I don't think that the high market jewelry industry is yet being threatened by synthetic diamonds.