In the world of gemstones, there is a rare category of diamonds that does not exceed 1% of global production, but it accounts for the largest share in terms of size and value.
This diamond, scientifically known as CLIPPIR, includes three of the largest stones ever known to humankind: the "Giant Cullinan" (3,106 carats) discovered in South Africa, the "Lesidi La Rona" (1,111 carats) which sold for $53 million after its discovery in Botswana in 2015, and the "Motseidi" (2,492 carats) which was extracted from Botswana in 2024.
But the material value of these stones, despite their enormous size, is not the only reason that drives scientists to study them. The real interest lies in the geological journey they have recorded over hundreds of millions of years.
The CLIPPIR diamond is not an ordinary diamond in terms of its origin, as it belongs to a group known as "ultra-deep" diamonds, which form at a depth of more than 400 km below the Earth's surface, in an area called the "mantle transition".
This depth is more than double that of ordinary diamonds, which form in the roots of ancient continents at depths of up to 200 km. The mantle, as geologists explain, is the thick, hot rocky layer between the Earth's core and its outer crust—a world directly inaccessible to humans, making rare diamonds like CLIPPIR precious windows into this hidden realm.
To understand the secrets of this diamond, geological research has focused on studying "kimberlite" rocks, which are rare volcanic magma rocks known to be the primary carrier of diamonds, as they transport diamonds and other minerals from the depths of the mantle to the Earth's surface.
Experts used the mineral olefin, the most abundant mineral in the mantle, as a tool to uncover these secrets. Kimberlite magma picks up this mineral as it rises, carrying with it a chemical signature of those deep rocks, including evidence of their iron content and oxygen isotope signatures, revealing the areas the kimberlite passed through and potential diamond storage sites.
Research has yielded significant discoveries that add new pieces to the CLIPPIR diamond mystery. Scientists have identified unusual iron-rich regions in the mantle, associated with the kimberlite containing these diamonds. According to the analysis, these regions originated from an ancient basaltic oceanic crust that was altered by hot fluids circulating on the seabed before being forced to the depths by tectonic plate movement, a process known as subduction. Under the immense pressure and heat, the carbon in this crust transformed into diamond, forming what we know today as CLIPPIR.
But research has also revealed a more complex aspect of this diamond's journey. The iron-rich rocks that hosted the diamond are so dense that they couldn't have risen to the surface on their own, contradicting previous theories that suggested they floated passively through the mantle. Instead, scientists believe they required immense lifting force, possibly via mantle plumes—piles of superheated rock rising from deep within the Earth, picking up dense material and propelling it upwards until it was stored in the lithosphere, the thick, solid root beneath the ancient continents, where it remained for hundreds of millions of years. Later, rare magma passed through these storage areas, rapidly rising to the surface and solidifying as kimberlite, carrying this precious diamond with it.
This helps geologists determine which kimberlite rocks deserve further examination.
In conclusion, the CLIPPIR diamond is not merely a rare gemstone; it is a journey through geological time, chronicling a voyage that began at the bottom of an ancient sea, passed through the depths of the mantle, reached the roots of the continents, and finally arrived at Earth's surface via rare volcanic eruptions. By analyzing the chemical evidence preserved in the rocks that carried it, we are beginning to understand not only where we might find these rare stones, but also what they reveal about the profound processes that have shaped our planet over hundreds of millions of years.
