One of the rarest, priciest, and most coveted gemstones is the pink diamond. With its frothy powder puff pale pinks to rich purplish reds, these diamonds are always fascinating. Each year, Rio Tinto’s Argyle Mine in the remote north of Western Australia produces just a handful of these treasures, which are sold through the Rio Tinto Diamonds Argyle Pink Tender. Scientists believe that pink diamonds get their color due to a phenomenon in the crystal lattice structure of the stone. Just how rare are pink diamonds? For every 1 million carats of rough diamonds produced at the Argyle Mine, which is the world’s most reliable source of pink diamonds, only 1 carat of rough is of the quality to qualify for the tender. The rough is polished at the Argyle Mine’s factory in Perth, Australia. The diamonds are graded and certified by the Gemological Institute of America (GIA), The Diamond High Council (HRD) in Antwerp and the AGT Gem Laboratory in Japan. This year, there were 65 diamonds in the tender, two of which were blue and one of which was a purplish red. The gems range in size from 49 points to 2.03 carats. Only 29 of the stones weighed more than 1 carat.
The 65 stones totaled 61.43 carats. These rare and precious diamonds comprise the tender, which travels from Perth to New York City, Tokyo, Hong Kong, London and Geneva during the fall. There are 120 dealers invited to the tender, where they examine the diamonds and then make a closed bid one or more stones or even all the stones. The winners and prices are never disclosed, but it takes a lot of green to be in the pink. According to Jean Marc Lieberherr, general marketing manager for Rio Tinto Diamonds, while one good quality, 1 carat white diamond may go for $20,000, it is possible that a good quality, 1 carat pink diamond could command as much as $400,000.