(IDEX Online) - A pair of blue diamond cluster earrings - 3.06 carats and 2.61 carats - are being offered with a high estimate of $8m at Sotheby's Hong Kong. Both pear modified brilliant-cut gems are GIA-certified as fancy vivid blue color, VS2 clarity.They are set with pear, oval and round diamonds, in platinum and gold, and signed DM (David Morris). Also in the sale is a 3.32-carat blue diamond ring is being offered at auction by Christie's Hong Kong with a high estimate of $6.4m.The fancy vivid blue emerald-cut stone is GIA-certified as internally flawless. It is set in a gold ring with 20 square-cut diamonds with a total approximate weight of 0.80 - 0.90-carat, on average G-H colour, VS-SI clarity.The Hong Kong Magnificent Jewels sale is on 28 November.