An enormous cushion-cut sapphire, formerly owned by Queen Marie of Romania, will be auctioned off by Christie’s on November 19 in Geneva. Weighing in at 478.68 carats, the gem is estimated to go for $860,000-$1,300,000. Christie’s claims it is the largest sapphire ever offered at auction. The same sale features two other significant sapphire jewels and a few D color, flawless diamonds as well. Bidders who haven’t depleted their funds can stay in town for Sotheby’s auction of a 103.83 carat flawless diamond the following day (reported here earlier).