But to get acquainted with this particular bit of bling, you'll need a cool £13.5 million to spare.'The Blue', the largest flawless vivid blue diamond in the world, is the centrepiece of the annual Christie's Magnificent Jewels sale taking place at the Four Seasons Hotel des Bergues in Geneva next month.The Blue is estimated to fetch between £12.5- £13.6 million and is the leading gem of the 250 lot strong sale, expected to rake in approximately £47.5 million.Just six months ago, Christie’s Geneva sold 'The Orange', the largest fancy vivid orange diamond in the world for £21million, a world record for an orange diamond .The sale of 'The Orange' also broke world records for price per weight of any diamond at £1.4 million per carat.The upcoming sale will also feature other spectacular coloured and colourless diamonds such as 'The Ocean Dream'. At 5.50 carats, the dazzling stone is the largest fancy vivid blue-green diamond in the world to come to auction, with an estimated value of £4.5 - £5.6 million.The combination of its size, natural origin, hue, and saturated colour makes it an extremely unusual stone.  Another rare coloured diamond in the sale is the light pink square-cut diamond of 76.51 carats. Set as a necklace it's likely to fetch £4-6 million.But if you're after a bargain, you could always try to nab a deal for just under a million with a necklace made from spinel, a type of gemstone made from magnesium.The seven spinel beads date back to the 17th century to the time of Mughal emperors.The gems were a symbol of the opulence and dignity of the empire, and were also treasured as protective talismans. So if you have a birthday or anniversary coming up, or just feel you deserve a little treat, book your man on a plane to Geneva and you never know what treats he might find.(dailymail.co.uk)ANN.Az