Pink diamonds are natural diamonds characterized by captivating shades from faint blush to vibrant magenta. These rare gems are highly sought after, with their unique coloration and extreme scarcity contributing to their exceptional appeal.
The Argyle Mine Legacy
The Argyle Diamond Mine in Western Australia was historically the world’s most significant source of pink diamonds. For over three decades, it supplied more than 90% of the global production of these rare stones. The mine commenced operations in 1983, transitioning to underground mining before ceasing activities on November 3, 2020, after 37 years, as its economic reserves were depleted. This closure marked a substantial shift in the supply of pink diamonds. Although the mine produced a vast quantity of diamonds, less than 1% were pink, underscoring their inherent rarity.
The Argyle pipe, a volcanic lamproite formation, provided unique geological conditions for their formation. This setting differed from the more common kimberlite pipes where most other diamonds are found. Argyle diamonds were characterized by low levels of nitrogen impurities, with their color attributed to structural defects within the crystal lattice.
Other Global Occurrences
While the Argyle Mine was the dominant producer, pink diamonds have been discovered in other regions globally, though in much smaller quantities. Historically, India’s Kollur mine was an early source. Brazil has also yielded pink diamonds from alluvial deposits in Minas Gerais, with finds continuing to the present day.
Discoveries in Russia, from the Alrosa mines, include a nearly 28-carat rough stone found in 2017. South Africa contributed with a 29.52-carat pink diamond in 2023. Canada’s Victor Mine in Ontario produced a 2.75-carat pink diamond, noted as the largest of its kind found in the country at the time. These other occurrences typically yield individual stones or limited production, contrasting sharply with Argyle’s historical output.
The Mystery of Their Color
The pink color in diamonds is attributed to plastic deformation, a structural anomaly within the diamond’s crystal lattice. Unlike most other colored diamonds, whose hues result from chemical impurities like nitrogen (yellow) or boron (blue), pink diamonds do not derive their color from trace elements.
Immense pressure and heat deep within the Earth cause atomic displacements, or structural defects, within the carbon atom arrangement. These defects alter how the diamond absorbs and refracts light, leading to a pink hue. This process involves the crystal structure bending and twisting, similar to how brown diamonds obtain their color. The extreme conditions required for plastic deformation explain why pink diamonds are found in specific and rare geological environments.
Rarity and Market Impact
The rarity of pink diamonds, especially following the Argyle Mine’s closure, profoundly impacts their market value. With the mine responsible for over 90% of the world’s supply now depleted, availability has diminished further. This constrained supply, combined with consistent demand, drives their exceptional prices.
Pink diamonds often command prices far exceeding colorless diamonds due to their scarcity. Their unique and constrained geological origins directly influence their unparalleled value and desirability. These rare stones are increasingly viewed as investment assets.