Argyle diamond mine in the remote East Kimberley region of Western Australia. The mine has been operating since 1983 and has produced more than 800 million carats of rough diamonds. It is one of the world’s largest supplier of diamonds and the world’s largest supplier of natural coloured diamonds.
The diamonds produced at the Argyle diamond mine are of an average low quality. Only 5% of mined diamonds are of gem quality, compared to a worldwide average of 20% (Author Janine Roberts contends that the “near-gem” quality rating is subjective and misleading because these diamonds can be cut into gems if desired. of the remaining 95%, they are about evenly split between classifications of “near gem quality” and industrial grade; 80% of Argyle diamonds are brown, followed by 16% yellow, 2% white, 2% grey, and less than 1% pink and green. Despite the low production volume of pink and red diamonds, the Argyle mine is the only reliable source in the world, producing 90 to 95% of all pink and red diamonds. Most Argyle diamonds are classified as type 1a , and have low levels of nitrogen impurities, their colour resulting instead from structural defects of the crystal lattice. Argyle diamonds tend to fluoresce blue or dull green under ultraviolet light, and blue-white under X-ray radiation. The most common inclusion is unconverted graphite, followed by crystalline inclusions of orange garnet, pyroxene, and olivine.
Annual Diamond Tender
Each year, a small collection of the best pink diamonds are offered in an exclusive sale known as the Argyle Pink Diamond Tender. For every 1,000,000 carats (200 kg) of rough pink diamonds produced by the mine, only 1 carat (0.20 g) polished will be offered for sale at the tender. It is an invitation-only event. Access to the collector’s edition catalogue and website access in itself is highly sought after.
In March 2009, Argyle announced their first ever tender of rare blue diamonds. The “Once in a Blue Moon” collection was sourced over several years, and comprised a range of precious blue and violet diamonds, which weighed in total 287 carats (57.4 g).
In 2016, the annual Argyle Tender became the highest selling tender in its 20-year history, according to the Diamond Investment & Intelligence Center