Editor’s Note
This article details the record-breaking sale of an 88.22-carat flawless diamond at Sotheby’s Hong Kong in 2019, highlighting the enduring allure and immense value of exceptional gemstones in the global luxury market.

On April 2, 2019, at a Sotheby’s auction in Hong Kong, an 88.22-carat oval-cut diamond (D color, Flawless, Type IIa) was sold to a Japanese private collector for HKD 108 million (approximately JPY 1.53 billion).
This was only the third time in auction history that an oval diamond over 50 carats had been offered. The winning bidder first saw the diamond at a preview held in Tokyo in March. After a bidding war between three participants, the final price of HKD 108 million (approximately JPY 1.53 billion) exceeded the pre-sale estimate of HKD 88-100 million (approximately JPY 1.25-1.42 billion), achieving a per-carat price of HKD 1.24 million (approximately JPY 18 million).

The diamond achieved the highest possible rankings in all four Cs (Color, Clarity, Carat, Cut). Its color is D (completely colorless, the highest grade for white diamonds). Its clarity is Flawless, meaning no internal or external imperfections are visible under 10x magnification. Its cut, polish, and symmetry are all graded Excellent, making it a perfect stone.
Like the oval-cut Koh-i-Noor and Cullinan I diamonds, part of the British Crown Jewels, this stone is classified as Type IIa, belonging to an extremely rare group comprising less than 2% of all diamonds. Type IIa diamonds are composed of pure carbon without nitrogen impurities, giving them exceptional transparency.
Rough diamonds that yield over 80 carats after polishing are exceedingly rare. The 242-carat rough for this diamond was found at the Jwaneng mine in Botswana, co-owned by De Beers and the Botswana government, a mine famous for producing very high-quality rough.
After its discovery, the rough was carefully cut and polished over several months into a well-proportioned and brilliant impressive oval diamond. The oval cut was chosen to preserve the maximum weight (carat) from the elongated shape of the rough. Cutting a stone of such significance requires immense skill and precision. This diamond was born from the high-level expertise and craftsmanship possessed by only a handful of diamond cutters worldwide.
In Chinese and other Asian cultures, the number 8 is considered a lucky number symbolizing “perfection, prosperity, and eternity.” The Chinese pronunciation of 8 (bā) is similar to that of 發 (fā), which means wealth or fortune, representing abundance. A double 8, like 88, is said to bring double happiness and is visually similar to the decorative character 囍 (meaning “double happiness”), making it a popular motif.
