The most expensive pink diamond in the world

The 170-carat Lulo Rose diamond may become the most expensive pink diamond at auction in the future.

The pink rough diamond is called Lulo Rose. Photo: Fox

One of the world's largest rough pink diamonds was discovered by miners in Angola in 2022, according to IFL Science . Named "Lulo Rose", the gem weighs 170 carats and could become the most expensive diamond in history. Its enormous weight is a factor, but the rare pink color also makes Lulo Rose highly valuable.

Colored diamonds are very rare, accounting for only 0.01% (1/10,000) of diamonds mined across the planet. Pink is as rare as blue, green, purple, orange and red, while yellow and brown are slightly more common. While the rarity of colored diamonds drives up the gem's price, beautiful color is the result of imperfection. The reason people dig up more transparent diamonds is because pure diamonds are more common.

Researchers don't know the exact mechanism behind pink diamonds, but they think it results from deformation. It is one of three ways a diamond can become defective (the other two are adulteration and damage). Deformation occurs when the diamond's lattice structure is twisted and bent, changing the way light reacts, making it no longer appear white.

That deformation needs to take place at the right level for the stone to be pink, because if it is too much, it will turn brown. The color of a diamond always accurately reflects the formation conditions. That's why defective diamonds are never the same. Therefore, pink diamonds are not the same color tone.

About 80 - 90% of pink diamonds found by humans are located in the same mine because they were born in areas with the same geological history. The Argyle Quarry in Western Australia, now closed, was a continental collision zone about 1.8 billion years ago. While the impact created a lot of pressure, the location near the bottom of the lithosphere provided a lot of heat, creating enough deformation for a range of colored diamonds, from pale pink to red, brown, orange and purple. Among them are many pink diamonds, but none as large as the Lulo Rose.

Before the discovery of Lulo Rose, the largest and most expensive pink diamond was the Pink Star sold in Hong Kong for 71.2 million USD in 2017. The stone weighed 132.5 carats but was cut into 59.6 carats. Therefore, many people predict that the 170-carat Lulo Rose may overtake the Pink Star to become the most expensive diamond in history at auction.