Miners discover a 37.4 carat diamond that is half pink and half colorless

A 37.41 carat rough diamond, split cleanly between pink and colorless, was discovered in Botswana. The stone came from the Karowe mine and was examined in Gaborone.

The work was led by Sally Eaton-Magaña, PhD, at the Gemological Institute of America (GIA). Her research focuses on diamond color and identification.

GIA describes a sharp boundary between the two halves. It also records dimensions of 1 by 0.63 by 0.57 inches.

Analysts noted that the diamond likely formed in two stages, and pointed out that similar stones examined in the past weighed no more than two carats.

They explained that the pink portion was probably colorless at first and later changed after intense geological pressure, while the colorless half formed afterward.

The finding is type IIa – a type of diamond with very low nitrogen. That purity makes the color contrast even more striking.

How pink diamonds get their color

Most pink diamonds owe their color to a distorted lattice, the ordered 3D pattern of atoms. This process changes how the crystal absorbs light.

Push the lattice too far and the hue turns brown, while too little leaves it colorless. In nature the key driver is plastic deformation, permanent bending of the lattice under stress.

Other colors often come from impurities or radiation that knock atoms out of place. Pink is different because the cause sits in structure, not chemistry.

In some stones the color gathers into narrow bands called lamellae, thin pink stripes within the crystal. Those bands often trace the slip planes where the lattice moved long ago.

Where and how diamonds form

Diamonds begin more than 100 miles down in the mantle, the thick rock layer beneath the crust. There, heat and pressure lock carbon into an exceptionally tight structure.

They reach the surface fast in kimberlite, a rare volcanic rock that carries diamonds. Quick travel keeps them from turning into graphite on the way up.

Many large stones are chemically simple, so their colors depend on defects and strain. That is why a two toned rough is such a clear record of the forces it felt.

Some diamonds form even deeper in the transition zone, a mantle layer 255 to 410 miles down. Their tiny inclusions act like sample bottles, preserving clues to ancient fluids.

Karowe mine is full of surprises

Karowe sits on very old continental crust that stayed cool and stable for eons. Conditions like that let diamonds survive and accumulate.

In 2024 the mine yielded the 2,488 carat Motswedi rough. Finds like that show how often Karowe turns up unusual material.

This half pink, half colorless rough diamond adds to that track record. It also gives researchers a built-in before and after in one crystal.

Modern recovery systems avoid crushing large crystals early in processing. That helps unusual rough reach the lab intact for study.

Links to ancient supercontinents

If deformation creates pink diamonds, then regions that squeeze or stretch crust at the right time may also play a role.

Scientists studying ancient continental movements have found that major shifts in Earth’s crust can set the stage for rare diamond colors. These shifts change pressure and temperature conditions deep below the surface.

Nuna, one of Earth’s earliest supercontinents, formed more than a billion years ago and united some of the oldest crust on the planet. Its long history of stretching and breaking reshaped deep mantle pathways where carbon rich fluids moved.

Those movements created windows where diamonds could grow or develop new structural features. That pattern helps explain why certain regions produce unusual colors while others do not.

Lessons from this pink diamond

A study linked Argyle pink diamonds to crustal extension during the breakup of supercontinent Nuna.

That timing fits a two-step story. Stress could have tinted one half first, with later growth adding a colorless section without strain.

This stone offers a rare geological timeline marker. The sharp boundary captures a shift in conditions that is usually hidden in microscopic features.

That makes it a useful natural experiment. It lets researchers compare spectra from the pink and colorless halves grown in the same rock.

Cutters may face a choice, preserve the boundary for science or chase the richest pink when planning the cut. Before any sawing, nondestructive tests map color zones and internal features to avoid damage.

Either way, the specimen will keep teaching. Its contrasting halves will help pin down the physics of defect centers, tiny lattice flaws that change how diamonds absorb light.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–