The Argyle Diamond Mine sporadically yields seldom-seen blue and violet diamonds. Violets are particularly enchanting and can make the beholder feel as though they are looking into a pool of lilac.

For every 25 million carats of rough diamonds unearthed from the mine, a single polished blue or violet tender stone is produced. And in the more than 30 years of the Argyle Pink Diamonds Tender, just 12 carats of polished violet diamonds has been offered.

Argyle blue or violet diamonds are not the result of boron impurities, but nickel or high concentrations of hydrogen, unlike the blue diamonds produced at other mines, that have boron. Boron is a trace element often present in blue diamonds, where it is known for transforming the lattice into a semi-conductor, which also absorbs light in the red region of the spectrum, causing a blue colour.

The Argyle Diamond Mine is the only consistent and known source of violet diamonds. Faceted blue or violet stones over half a carat are very rare, and only a few weighing more than one carat have been found at the mine. 2009 marked the first exclusive tender of blue and violet diamonds, selected from several years of production.

In 2012, the last three singular stones profiled here were part of the aptly named ‘Once in a Blue Moon’ collection of the tender - a selection that took two years to collect.