Rarer than Diamonds . . .

The sale of the Royal Blue necklace for a record $16.2m last week demonstrates just how rare and how desirable Kashmir sapphires are.

The diamond world has its Golcondas, the sapphire world has its Kashmirs. Both are highly prized and extremely rare. Both come from legendary mines that were exhausted well over a century ago.

But there's a key difference, as we'll see, that makes Kashmir sapphires even rarer than Golconda diamonds. Though not necessarily more valuable.

The story of the Golconda diamonds is remarkable. They were the first diamonds ever known to mankind, discovered 2,000 years ago in southern India. And they remained the world's only known source of diamonds until the 1720s, when the first non-Golconda diamonds were discovered in Brazil.

Extracting diamonds at the time was a highly labor-intensive process, even in the 16th to 18th centuries, when production across Golconda alluvial mines hit its peak.

There was no mechanization. Workers would scoop up gravel from river beds by hand, sift out the finer material with a tight mesh and scan what remained by eye for diamonds.

Kollur mine, the largest of all Golconda mines (and source of the famed Koh-i-Noor), employed up to 60,000 workers at one point to do exactly that.

Commercial mining started in around 1560 and came to an end in the 1830s when the last of Golconda's 23 mines was depleted. In all that time no more than 10m carats were recovered.

Unsurprisingly, very few Golconda diamonds have survived. And their rarity is reflected in the prices they fetch. In April 2013 the Princie Diamond, a 34.65-carat fancy intense Type IIa pink diamond, sold for a record $39.3m at Sotheby's New York. That's $1,134,199 per carat.

The story of Kashmir sapphires is markedly different. The Golconda mines were active for almost three centuries. The golden age of Kashmir's premium sapphire mine lasted just six years. And the climate there was so harsh that mining only took place during three summer months, so six years was, in practice, just 18 months.

It was in 1881 that a landslide exposed sapphire-bearing pegmatitic rocks 13,000 feet up in the remote Zanskar range of the Himalayas.

Local shepherds and villagers - several hundred, a thousand at most - would use basic hand tools to dig through the sapphire-yielding rock at the Old Mine.

In the short bursts they were able to work, they recovered no more than 1m carats of corundum rough (the base mineral for both sapphires and rubies). Only a fraction of that, let's hazard a guess at 100,000 carats, was gem-quality sapphires.

So Golcondas, rare though they are today, were mined readily at many sites by many workers for many years. Kashmir sapphires, by contrast, were mined by very few people at only one significant (and very remote) site, for only a tiny window of time.

Which brings us back to last week's highly-anticipated auction at Christie's Magnificent Jewels live auction in Hong Kong.

The Royal Blue necklace, a modern creation with 104.61 carats of Kashmir royal blue sapphires (and 121.81 carats of diamonds) sold for $16.2m (pre-sale estimate of $13m to $19m).

Given the extreme rarity of Kashmir sapphires, you may have thought the price would have been even higher.

Even ordinary sapphires are far rarer than diamonds. Current production of gem quality sapphires is under 10m carats a year, compared to 118m of rough diamonds in 2024. And, as we've seen, the highest-end sapphires are far rarer than the highest-end diamonds.

But sapphires' problem is that they've never been a girl's best friend. They may be long-lasting, but they've never been marketed as "forever". Sapphires may be favored by connoisseurs, but diamonds remain the global symbols of wealth, beauty and status. Which is why the most-prized diamonds still command the highest prices.

Have a fabulous weekend.