[Rockhounds] The 'super-deep' royal diamonds revealing Earth's secrets

[Kreigh Tomaszewski]

The package arrived in a plain cardboard box. It was simply addressed to S
Neumann & Co – a mining sales agency in the centre of London – and weighed just
over a pound
<https://timesmachine.nytimes.com/timesmachine/1905/04/14/101357466.pdf?pdf_redirect=true&ip=0>
 (around 500g). But this was no ordinary cargo.

It was April 1905, and three months earlier, the surface manager at the
Premier Mine in South Africa had been completing a routine inspection 18ft
(5.4m) underground, when he glimpsed a reflected light in the rough wall
above him. He assumed it was a large piece of glass hammered in by
colleagues as a practical joke
<https://books.google.co.uk/books?id=UN5OBwAAQBAJ&printsec=frontcover>.
Just in case, out came his pocket knife, and after some digging… the knife
promptly snapped. Eventually the rock was removed successfully, and
revealed to be a bona fide diamond – a monster 3,106.75-carat stone
<https://www.gia.edu/doc/SU06A2.pdf>, almost the size of a fist. It was not
only enormous, but unusually transparent.

The Cullinan, as it became known, is the largest diamond ever found. Once
it had been polished and cleaved into several more manageable stones
<https://www.gia.edu/doc/SU06A2.pdf>, the largest crystal it yielded would
shine like the cool glow of a star in a distant galaxy. As a result, this
stone – the Cullinan I – is sometimes known as the Great Star of Africa.

Nearly 120 years later, the mega-diamond has not been forgotten. During the
late Queen Elizabeth II's funeral procession, several of the Cullinan's
descendants were placed on the Monarch's coffin, and rode along with her –
they were only removed as she was lowered into the royal vault. That's
because today these giant gems are part of the Crown Jewels, normally kept
in the Tower of London and brought out for state events – the Cullinan I
now resides in the British Sovereign's Sceptre, while its next-largest
sibling, the Cullinan II, is embedded in the Imperial State Crown.

However, before the rough diamond could have its makeover and take its
place in history, it needed to be sold – and London was chosen as the most
promising location to do this. This presented a problem: how do you
transport such a valuable stone 7,926 miles (12,755km), without it being
stolen?


In the end, the precious rock was sent all the way from Johannesburg by
ordinary registered post, at a cost of just three shillings or about 75 US
Cents
<https://timesmachine.nytimes.com/timesmachine/1905/04/14/101357466.pdf?pdf_redirect=true&ip=0>
at
the time (around £11.79 or US$13.79 today
<https://www.in2013dollars.com/uk/inflation/1905?amount=0.05>). Meanwhile,
a replica of the diamond made the long voyage to London by steamboat – it
was placed conspicuously within the captain's safe and guarded by police
detectives as a decoy. Amazingly, both made it to their destination. After
years of failing to sell, the diamond – the real version, this time – was
purchased by the Transvaal government for £150,000 (£20m or US$22.5m today)
and gifted to King Edward VII.

But though they're renowned across the globe for their size and
transparency, these characteristics are no accident. The Cullinan was a
"Clippir" diamond <https://www.gia.edu/doc/GG-WN17-Smith.pdf> – a member of
a special category of the very largest and clearest examples ever found.
And there is more to them than meets the eye.


https://www.bbc.com/future/article/20220922-the-super-deep-royal-diamonds-revealing-earths-secrets