Miners Unearth Extraordinary 37.41-Carat Bicolor Diamond in Botswana: Half Pink, Half Colorless
In a groundbreaking discovery that has captivated gemologists, scientists, and diamond enthusiasts alike, miners at Botswana’s renowned Karowe mine have recovered a remarkable 37.41-carat rough diamond distinguished by its striking division: one half a vivid pink and the other perfectly colorless. This rare bicolor gem, unearthed in August 2025 and examined by experts at the Gemological Institute of America (GIA) laboratory in Gaborone, represents an unprecedented find in both size and formation.
The diamond measures approximately 24.3 × 16 × 14.5 millimeters and belongs to the elite Type IIa category—known for its exceptional chemical purity due to minimal nitrogen impurities. This purity accentuates the sharp contrast between the two color zones, creating a clear, natural boundary that experts describe as “sharp” and visually dramatic.
According to GIA researchers, including senior manager of diamond identification Sally Eaton-Magaña, the gem’s dual appearance reveals a complex geological history formed in two distinct stages deep within Earth’s mantle, more than 100 miles below the surface. The pink section likely originated as colorless but underwent plastic deformation—intense tectonic forces, possibly linked to ancient mountain-building events millions of years ago—that twisted its crystal lattice just enough to scatter light and produce the characteristic pink hue. The colorless half crystallized later, under more stable conditions, remaining untouched by the same stresses.
This two-phase growth process explains the gem’s unique split. While smaller bicolor pink-and-colorless diamonds (typically no more than 2 carats) have been documented before, this 37.41-carat specimen stands out as “astounding” and unparalleled in modern history for its scale.
Pink diamonds are among the rarest gems on Earth, comprising less than 0.01% of all diamonds recovered. Their color stems not from chemical impurities but from structural distortions in the crystal lattice—a delicate balance where insufficient stress leaves the stone colorless, and excessive pressure turns it brown. This find represents a “Goldilocks” scenario, where conditions were precisely right to yield the coveted pink tone in one section while preserving clarity in the other.
The Karowe mine, operated by Canadian company Lucara Diamond Corp., has long been a hotspot for exceptional diamonds. Located on ancient, stable cratonic crust, it has produced some of the world’s most significant rough stones in recent years, including the 2,488-carat Motswedi (the second-largest rough diamond ever discovered, recovered in 2024), the 1,758-carat Sewelô, and the 62-carat (or 63-carat in some reports) Boitumelo, Botswana’s largest fancy pink diamond to date. The mine’s track record of yielding large, high-quality Type IIa gems underscores why such extraordinary discoveries continue to emerge from this location.
The GIA’s analysis, detailed in their publication Gems & Gemology, highlights the stone’s scientific value. Beyond its potential as a future high-value polished gem—pink diamonds often command premium prices at auction—this bicolor rough serves as a “frozen snapshot” of Earth’s dynamic geological past, offering insights into mantle processes, tectonic history, and diamond formation.
While its ultimate fate—whether it will be cut into one or multiple polished stones—remains to be determined, the discovery reaffirms Botswana’s status as a premier source of the world’s most remarkable diamonds. Nature, once again, has delivered a true marvel from the depths. 💎
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