The CTF Pink Star
The CTF Pink Star
The most valuable gemstone ever sold at auction
The CTF Pink Star is a 59.60-carat oval mixed-cut diamond graded Fancy Vivid Pink, Internally Flawless by the Gemological Institute of America — the largest diamond of its colour grade ever assessed by that laboratory. On 4 April 2017, the stone sold at Sotheby's Hong Kong for US$71.2 million (HK$553 million), establishing the highest price ever achieved at auction for any gemstone. The buyer was Chow Tai Fook Enterprises, the Hong Kong-based jewellery conglomerate, which renamed the stone in honour of its founder, Cheng Yu-tung, whose initials are CTF. No subsequent auction result has surpassed this figure, cementing the CTF Pink Star's position as the definitive benchmark for the top of the coloured-diamond market.
Origins and Recovery
The rough crystal was recovered in 1999 from De Beers' Premier Mine in Cullinan, Gauteng, South Africa — the same deposit that yielded the Cullinan Diamond in 1905 and remains one of the world's most prolific sources of large, gem-quality pink and blue diamonds. The rough weighed 132.5 carats, an extraordinary size for a pink diamond of gem quality. Pink colour in diamonds is generally attributed to plastic deformation of the crystal lattice during or after formation, producing graining planes that selectively absorb green light; the Premier Mine's deep-mantle geology appears particularly conducive to generating such structural anomalies at large scale.
Cutting and the Steinmetz Years
De Beers transferred the rough to Steinmetz Diamonds, the Antwerp- and Tel Aviv-based cutting house renowned for its work on exceptional fancy-colour material. The polishing process took approximately twenty months, a reflection of the extreme care required to maximise both weight retention and colour saturation in a stone where each carat of finished weight represents enormous value. The finished oval, weighing 59.60 carats, was unveiled in 2003 under the name the Steinmetz Pink and exhibited at the Smithsonian Institution in Washington, D.C. alongside other legendary diamonds. The GIA certificate confirmed the Fancy Vivid Pink grade — the highest saturation designation on the GIA colour scale — and the Internally Flawless clarity grade, a combination of attributes essentially without precedent at this size.
First Auction and the 2012 Sotheby's Sale
The diamond was consigned to Sotheby's Geneva in November 2013 under the name the Pink Star, where it was offered with a pre-sale estimate of US$60 million. Bidding reached US$83.2 million — a world record at the time — but the winning bidder, New York diamond dealer Isaac Wolf, subsequently defaulted on payment. Sotheby's was obliged to take the stone onto its own books, recording a loss on the transaction. The episode illustrated the operational risks inherent in the ultra-high-value end of the auction market and drew considerable commentary from the trade regarding the adequacy of buyer qualification procedures at that price level.
The 2017 Hong Kong Sale and the Record
Sotheby's re-offered the stone in Hong Kong in April 2017, this time achieving a clean sale. The hammer price of HK$500 million, with buyer's premium bringing the total to HK$553 million (US$71.2 million), surpassed the previous verified auction record for any gemstone — the US$57.5 million paid for the Oppenheimer Blue diamond at Christie's Geneva in May 2016. The per-carat price of approximately US$1.19 million was itself a record for any diamond or coloured stone sold at auction. Chow Tai Fook's acquisition and the subsequent renaming to CTF Pink Star were widely interpreted as a statement of brand prestige as much as a financial investment, consistent with the company's long-standing strategy of associating its name with landmark gemstones.
Gemmological Significance
The CTF Pink Star's GIA grading report places it in a category that is, for practical purposes, unique. The criteria that converge in this stone are worth enumerating:
- Size: At 59.60 carats, it is the largest Fancy Vivid Pink diamond ever graded by the GIA, by a substantial margin.
- Colour grade: Fancy Vivid Pink represents the apex of the GIA's saturation scale for pink diamonds; the vast majority of pink diamonds of any size fall into the Faint, Very Light, or Light categories.
- Clarity: Internally Flawless in a stone of this weight is exceptional for any diamond; in a pink diamond, where the colour-causing plastic deformation typically introduces graining and internal stress features, it is remarkable.
- Type IIa classification: The stone is a Type IIa diamond, meaning it contains no measurable nitrogen impurities — the category associated with the finest colourless diamonds and with many of the world's most celebrated pink and blue stones.
The combination of these four attributes in a single stone has led gemmologists and auction specialists to describe the CTF Pink Star as effectively irreplaceable: no comparable rough has been reported from any mine since the original 1999 recovery.
Market Context and Investment Significance
The CTF Pink Star sale is routinely cited in discussions of coloured-diamond investment as the clearest demonstration that exceptional fancy-colour diamonds can achieve prices per carat that dwarf those of any other portable asset class. The stone's trajectory — from a 1999 rough recovery through a failed 2013 auction to a 2017 record — also illustrates the complexity of the ultra-high-value market: liquidity is limited, buyer pools are narrow, and the consequences of a failed transaction can be severe even for a major auction house. Nonetheless, the eventual outcome validated the fundamental scarcity argument: a stone with no gemmological equal will, given sufficient time and the right market conditions, find a buyer willing to pay a generational price. For investors and collectors, the CTF Pink Star functions as a reference point against which all other large fancy-colour diamonds are implicitly measured.