The De Beers Millennium Blue Diamond, a magnificent 5.16-carat pear-shaped internally flawless fancy vivid blue diamond, will be a highlight at the upcoming Magnificent Jewels & Jadeite sale April 7 in Hong Kong. The high estimate of the rare blue diamond is $5.8 million, making it among the most expensive diamonds Sotheby’s has ever sold in Hong Kong.

The De Beers Millenium Blue Diamond

De Beers Millennium BlueThe sale will offer an array of diamonds, gemstones, jadeite and natural pearls across more than 320 lots, with an estimated total value of more than $47 million.

Sotheby’s has noted two high-valued items expected to be sought-after by collectors. The first is an exceptional jadeite and diamond necklace by Cartier, estimated between $4.9 million and $6.4 million that is made up of 35 jadeite beads of highly translucent vivid emerald green color strung as a single strand and enclosed with a platinum clasp. The clasp is set with circular-cut diamonds.

Another item marked as “highly important” is the diamond rivière necklace. Estimated between $4.1 million and $5.2 million, the straight-line necklace is composed of 50 graduated brilliant-cut diamonds ranging from 1.50 to 6.55 carats, with a total weight of 107.43 carats, mounted in platinum.