Sotheby’s Hong Kong spotlights 28.88-carat De Beers diamond in Luxury Week

A 28.88-carat D-flawless diamond rarely arrives at auction with this much clarity of story and scale. Sotheby’s put the De Beers Jwaneng 28.88 at HKD 17,000,000 to HKD 22,000,000, positioning the unmounted stone as the headline lot in Hong Kong Luxury Week and as a clean read on what still commands the highest prices: color, clarity, size, and provenance.

The numbers matter because they show just how little of the original crystal survived the journey from mine to polished gem. The stone began as 114.83 carats of rough and was cut into a 28.88-carat round brilliant, which means only about a quarter of the original weight remained in finished form. That kind of yield loss is where value gets made and lost in diamonds. A D-color stone sits at the top of the colorless scale, flawless means no visible inclusions or blemishes under magnification, and Type IIa identifies a chemically exceptional category long associated with the rarest white diamonds. In plain language, this is the kind of stone where every stage of cutting had to preserve value while chasing perfection.

Its provenance sharpens the appeal further. The diamond came from Botswana’s Jwaneng mine, whose name means “little stone,” a wry label for a source that has been producing since the early 1980s and is widely regarded by De Beers as one of the world’s most valuable mines by value. Sotheby’s cast the lot as the opening note in a new collaboration with De Beers, a framing that turns the diamond into more than a jewel: it becomes a narrative of extraction, transformation and scarcity. The 28.88-carat weight also carries favorable associations in Chinese number symbolism, a detail that matters in Asian markets where numerology can influence collector appetite as much as gemological pedigree.

Sotheby’s High Jewelry sale in Hong Kong widened that conversation beyond one diamond. Cartier, Bulgari and Van Cleef & Arpels all appear in the selection, alongside Kashmiri sapphires, Colombian emeralds and rubies from Burma, while blue and pink diamond rings underscore the pull of colored stones at the top end. Luxury Week in Hong Kong runs alongside sales in handbags and accessories and other fine jewelry categories, reflecting Sotheby’s cross-collecting strategy across luxury. But the Jwaneng diamond still tells the clearest market signal: at this level, buyers are paying for rarity that can be measured, traced and proved.