Lucara's True Blue Wonder

Lucara is no stranger to exceptional diamonds. And exceptional prices.

Its 1,109-carat Lesedi La Rona sold for $53m and the 813-carat Constellation for $63m, both as rough stones.

They were both colorless gems. This week it announced the recovery of a remarkable blue diamond, weighing 36.92 carats. It's a seriously valuable stone.

Let's go back to colorless for a moment. The world's finest colorless diamonds command huge per-carat prices.

The record is $260,000, for a 118.28-carat oval D flawless Type IIa diamond that sold at Sotheby's Hong Kong in October 2013 for $30m. Closely followed by the 101.73-carat Winston Legacy, which sold for $26.7m - $254,400 per carat - at Christies' Geneva in May 2013.

But when it comes to blues, the sky really is the limit. The record is currently held by the Blue Moon of Josephine Diamond, a 12.03-carat stone, which sold for $4.03m per carat (total price $48.5m) at Sotheby's Geneva in November 2015. That's almost 16 times the per-carat record for colorless gem.

Nobody can say what Lucara's new blue - its biggest blue recovery by a long way - will fetch, either in its rough state or as a polished stone.

We don't know enough about the physical properties of the stone or how it will be cut. And if it ends up being auctioned - which is not a given - much will depend on bidders' emotions on the day, quite aside from more predictable market factors.

But even with all these caveats, we can speculate.

Color intensity will make a huge difference. A fancy vivid - the highest level of color saturation - can fetch two or three times the price of a fancy intense counterpart.

As for the cut, a realistic estimate would be 45%, which would result in a polished diamond of around 16.6 carats.

That's bigger than the De Beers Cullinan Blue, the largest polished fancy vivid blue diamond ever sold at auction. It was 15.10 carats and fetched $57.5m at Sotheby's Hong Kong in April 2022.

Or the 14.62-carat fancy vivid Oppenheimer Blue, which sold for the same price at Christie's Geneva in May 2016.

The 23.24-carat Golconda Blue was the largest fancy vivid blue ever offered at auction (May 2025 at Christie's Geneva) with an estimate of $35m to $50m, but it was pulled a couple of weeks before the sale, reportedly because the consignor decided to sell it to a family member instead.

So that's some of the relevant background on Lucara's new blue. Draw your own conclusions, name your own price.

I'll finish with a snippet of diamond news from my home country that should raise a smile.

A diamond described as the UK's "biggest in a decade" - 23.36-carats - sold at auction (on 18 March) for just over its high estimate of £1m ($1.34m).

It beat a record held by a gem that was bought for just £10 ($13) - yes, you read that right - from a "car boot sale" (swap meet, garage sale) in London.

The buyer, and no doubt the seller, assumed it was costume jewelry. It was only 33 years later that the owner had it valued. It turned out to be a 26.29-carat diamond (I / VVS2) that sold at Sotheby's in 2017 for almost $850,000.

Have a fabulous weekend.