Rare white diamond expected to sell for up to $30m in Geneva

The Rock is the largest white diamond to ever appear at auction

The hardest natural substance on earth, a symbol of strength, wealth, power and love, diamonds have captivated humans since they were first discovered in alluvial deposits along the river Pennar in India over 2,000 years ago.

Now, Christie’s has announced that it will auction The Rock, a 228.31 carat pear-shaped diamond, and the largest white diamond to ever appear for sale at auction, at its Magnificent Jewels sale on May 11th in Geneva. Described as “an exceptionally rare gemstone”, mined and polished in South Africa over two decades ago, the house estimates the stone will achieve between $20- $30 million (€18-€27m).

Graded by the Gemmological Institute of America (GIA) with VS1 clarity (very slightly included 1) it comes with a letter from the institute stating that “it is the largest existing D-Z colour pear shaped diamond ever graded by the laboratory”. Its colour is graded G, which is near colourless. This shows the difference in value given to colourless versus black diamonds: Sotheby’s achieved £3.2 million (€3.79m), excluding fees, for the Enigma in January 2022, a 555.55 carat black diamond purported to have come from space.

The previous auction record for the largest white, colourless diamond was a 163.41 carat stone, sold through Christie’s in 2017 for $33.7 million (€30.5m), which was the centrepiece of a sensational diamond and emerald necklace.

In terms of size, The Rock is under half the weight of the Star of Africa, a stone cut from the Cullinan diamond – the largest rough diamond ever mined. The Star of Africa, at 530 carats and the size of a golf ball, is not likely to be up for sale anytime soon however; it sits in the Sovereign’s Sceptre with Cross, which is part of the UK crown jewels and has been used at every coronation since Charles II’s in 1661.

Diamond supply

The recent sanctions imposed by the United States and European nations on Russia due to the invasion of Ukraine could impact the price and supply of diamonds.

Russian mines are the largest producers of diamonds in the world, accounting for about 30 per cent of the global market. Alrosa, Russia's colossal state-backed mining monopoly, accounts for about 99 per cent of all rough diamonds produced by the Russian Federation, with reported sales of $4.1 billion in 2021.

But complicating the sanctions is the fact that the bulk of these diamonds go to India to be cut, prior to being sold across the world. This essentially creates a loophole with provenance, as they are deemed to have undergone a significant transformation, and hence can be imported as an Indian product.

Added to this, Gokhran (the Russian state precious metals and gemstones repositor), a unit of Russia's ministry for finance and the state depository for holding inventories of diamonds, has attempted to "regulate" the diamond market. It buys in times of excess and holds auctions during shortages, though the company says that it has "prevented the price of diamonds from skyrocketing" and "helped stabilise the diamond market", as claimed by deputy finance minister Alexey Moiseev in December 2021.

Reserves at Gokhran and Alrosa are unknown, but there has been an international call on the industry to regulate the global supply chain of these billion year-old nuggets. christies.com