Max Pearson

speaker

1,342 appearances 10 recordings 1 series first heard Dec 2025 last heard 11 Apr

Max Pearson’s voice in public audio — every appearance, attributed to the second.

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Recordings per month over the last 12 months — 10 in all, peaking in Jan 2026 with 3.

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The History Hour · Blood diamonds and the meeting between Florence Nightingale and Aga Khan III · 28 Feb 2026 podcast

I think there was a notable Scottish scientist called James Hannay who was essentially making ever more robust pipe bombs and inside the pipes were carbon-rich oil and he would blow them up and hope that diamonds were produced.

But gradually the equipment became more and more technical, largely based on the work of an American physicist, Percy Bridgman, who won the Nobel Prize for high pressure physics in the 1940s.

There were two teams that managed to grow diamonds in what was called the high pressure, high temperature method, both in the 1950s.

But actually, they weren't the first to grow diamonds.

There was another approach which won the race to grow artificial diamonds by a month.

It was called chemical vapour deposition.

The diamonds are grown in relatively low pressures at relatively low temperatures of around 1,000 degrees centigrade.

We start off with a chamber and carbon-rich gases are added to this chamber.

So typically methane, which is a mixture of hydrogen and carbon.

And that gas is heated and turned into a plasma.

So when it's a plasma, what's happening is the molecules of the gas are being broken apart.

And so...

The carbon becomes free, free of the hydrogen bonds.

And then the carbon atoms move around the chamber before they're eventually settled on a seed of diamond, which is placed in a slightly cooler area of the chamber.

That seed diamond grows a bit like how you see water condensing on a cool window.

In the winter, it might cool on a car windscreen and crystallise to ice.

So that's the second approach to growing diamonds called chemical vapour deposition, increasingly mainstream in the market today.

That's the gemologist and author James Evans.

Next, to Syria and the civil war which engulfed the country from 2011 onwards was one of the deadliest and most destructive conflicts to emerge out of the Arab Spring.

But amongst the chaos, a group of young men in the besieged town of Darayya came together to build a secret library, a symbol of hope for a fractured community.

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