Lucara Recovers Rare 37-Carat Blue Diamond at Botswana Karowe Mine

A 36.92-carat blue diamond, classified as a rare Type IIb, emerged not from fresh excavation at Lucara Diamond Corp.'s Karowe mine in Botswana but from ore that had already been stockpiled, recovered through X-ray transmission machinery that scanned the material with high-energy X-rays and separated the stone using precision air jets before it ever reached a crusher.

The recovery, announced in mid-March 2026, is only the second special blue Lucara has found at Karowe since the mine produced a 9.74-carat blue alongside a 4.13-carat pink in 2019. Type IIb diamonds owe their color to the presence of boron within the crystal lattice, a characteristic that places them among the rarest and most commercially consequential stones in the rough market.

"Lucara is delighted to announce the recovery of this stunning blue, high-quality diamond from the Karowe mine, which again reinforces the special nature of this asset," said William Lamb, President and CEO of Lucara. "Recoveries such as this demonstrate the value contained within the company's surface stockpiles, which remain an important source of mill feed and a contributor to ongoing diamond recoveries."

That stockpile has been quietly productive. Since the beginning of January, Lucara retrieved five separate stones exceeding 100 carats by processing stockpiled ore at Karowe, making the 36.92-carat blue a significant but not isolated result from material that conventional logic might have dismissed as already worked.

The XRT process that surfaced the stone works by detecting density differentials: diamonds are less dense than the surrounding host rock, so the system flags them even when they are entirely concealed from view. Once identified, targeted air jets divert the stone into a sealed collection chamber, bypassing the mechanical crushing that has historically fractured large roughs during processing.

The timing of the recovery matters in financial context. Lucara reported that 2025 revenue fell 22% to $159.7 million and profit dropped 35% to $26.1 million, with the company navigating a period of moderated rough diamond demand and a shortage of the larger stones that generate disproportionate revenue. The Karowe mine, which has been in continuous production since 2012, is currently transitioning from open-pit to underground operations through the Karowe Underground Project. Underground development ore is scheduled to begin offsetting stockpiles in 2027, with full-scale underground production planned for the first half of 2028.

Until those underground volumes materialize, surface stockpiles remain the operational bridge, and a 36.92-carat blue Type IIb is a persuasive argument that the bridge still holds considerable value.