Here's Why Size Doesn't Always Matter

The world's second-biggest rough diamond has, finally, found a buyer.

The discovery in August 2024 of what is now known as the Motswedi diamond, at Lucara's Karowe mine, in Botswana, grabbed headlines far beyond the diamond media.

At 2,488 carats it was second only to the iconic 3,106.75-carat Cullinan, mined in South Africa way back in 1905 and now apart of the British Crown Jewels.

But size isn't the only thing that matters. The GIA, which subsequently examined the stone in great detail, concluded it was a diamond of undoubted "historical significance". But that doesn't necessarily mean it's going to break any price records.

The GIA described it as a transparent, gem-quality diamond that displays a light brown color - attributes that in any smaller stone these would be wholly unremarkable.

Lucara's CEO William Lamb noted early on that it "wasn't as colorless as the 1,109-carat Lesedi La Rona" - which was bought by British jeweler Graff Diamonds in 2017 for $53 million.

He acknowledged that it contained inclusions with brown tones - a candid admission that quality, not just carat weight, would drive value.

Buyers who could afford such a stone would, in truth, more likely opt for something less enormous, but with more dazzle.

Lamb also said a number of museums had expressed an interest in displaying it, uncut, as a wonder of nature.

That almost certainly hasn't happened, given that the stone appears to have been sold through Lucara's agreement with the Antwerp-based cutter HB Trading.

Under a 10-year deal, HB handles all of Lucara's +10.8-carat stones. Botswana technically retains the right to exempt "legacy stones" worth over $10 million, but did not exercise that right for Motswedi.

Lucara announced the sale of the stone during Q2 2026, in its latest financial results, it provided only a vague indication as to the price it fetched.

Total revenue for the year was $41.0 million, a figure that includes the sale of other stones, the Motswedi must have sold for less than that.

And less than $33.9 million, the contribution for that quarter from HB.

HB's average quarterly run-rate has been around $26 million, if you strip out mega-stone outliers like 549-carat Sethunya and the 1,080-carat Eva Star, and.

If Q2's performance was in line with expectations, that would leave roughly $8 million unaccounted for - which is an implausibly low figure for a 2,488-carat stone, even one with brown tones.

We don't know what the actual figure is, but we can say with some certainty that the Motswedi has achieved notably less per carat than other Lucara stones, such as Lesedi La Rona, at 1,109 carats ($47,800 per carat), Constellation, at 813 carats ($77,500 per carat) and Seriti, at 1,094 carats ($18,200 per carat).

The stone created something of a stir when it was recovered. It was initially reported at 2,492 carats — big enough to fill the palm of your hand — but the size was later revised down to 2,488.32 carats after cleaning and handling removed 1.50 carats in small fragments.

Botswana's then-president, Mokgweetsi Masisi, lauded it as "a symbol of national pride and economic importance" and there was a national competition to name it that attracted 39,000 entries.

But bigger doesn't always mean better. And historical significance doesn't necessarily equate to commercial value.

Have a fabulous weekend.