The first auction of a red diamond in Australia gathered a lot of attention but at the end of the day there was no sale. The Sotheby's Australia's April 12 sale featured the first red diamond ever offered for public auction in Australia. The stone in question is a 0.82-carat, fancy purplish-red Argyle diamond set into a ring with a pair of fancy blue diamonds all surrounded by brilliant-cut white diamonds mounted in platinum. It was estimated at between 700,000 and 1 million Australian dollars (between about $645,065 and $921,556) but although there was a lot of interest before the auction the bidding started at $480,000 and stalled out at $490,000.
Red diamonds are exceedingly rare. It's not known exactly how red diamonds are produced in the earth, it is believed that plastic deformation of the stone's crystal is the cause. As diamonds were pushed up kimberlite pipes from deep inside the earth toward the surface they were exposed to tremendous heat and pressure. This can cause areas of deformation in the crystal structure thereby changing it so that it can only absorb light in different areas of the visible spectrum. Instead of a rainbow you get a single color, often a pink, purple or red tone. This is different from other colored stones such as blue diamonds which form because of the addition of boron or green diamonds which are impacted by natural radiation. There are only around 100 natural red diamonds believed to have been discovered and just three over five carats: Moussaieff red, the Kazanjian red and the De Young red diamond.
ABC News in Australia reports that all is not lost for this red stone, it will likely sell behind the scenes, albeit for less money. The website reports that Margo Fitzgibbon, a diamond collector from Sydney, will make another offer for the ring and believes that there will be others who will be looking to buy as well. She predicted it will sell for around $800,000 or $900,000 Australian, possibly to an overseas buyer.