A newly discovered rough diamond from Botswana has stunned scientists by preserving two distinct geological histories within a single crystal — one half pink, the other perfectly colourless. The rare find is offering fresh insight into how some of the world’s most elusive pink diamonds are formed deep inside the Earth.
A diamond unlike most others
The 37.41-carat diamond was recovered from the Karowe Mine and analysed by scientists at the Gemological Institute of America (GIA) in Gaborone. Classified as a Type IIa diamond, it contains extremely low nitrogen levels, making it chemically pure and ideal for geological study.
What makes the stone exceptional is its sharp, clean division. Researchers believe the pink section formed first and later underwent intense structural stress, while the colourless half grew afterwards under calmer conditions.
Why pink diamonds are so rare
Unlike yellow or blue diamonds, pink diamonds owe their colour not to trace elements but to plastic deformation. Extreme pressure bends the crystal lattice, altering how light travels through the stone. Too much stress results in brown diamonds; too little leaves them colourless.
In most pink diamonds, colour appears in thin bands. In this specimen, however, the boundary between the two zones is clear, offering scientists a rare natural comparison within a single crystal.
Clues from deep Earth history
The diamond formed more than 160 kilometres below the surface and was carried upward by kimberlite magma. Similar processes have been studied at Australia’s Argyle mine, whose pink diamonds were linked to tectonic stress during the breakup of ancient supercontinents, as reported in Nature Communications.
Researchers say the Botswana diamond supports the theory that large-scale tectonic events play a key role in creating pink diamonds.
Science before sparkle
Before any cutting is considered, the diamond will undergo further non-destructive testing. While the pink half may be commercially valuable, scientists say the intact crystal is far more valuable as a rare record of Earth’s deep interior.