Natural Diamonds

Blue diamonds are one of nature’s rarest treasures in the world. The natural blue colour is derived from the chemical element Boron, which is trapped in the crystal carbon structure during their formation. A diamond can be blue with less than one boron atom per million of carbon atoms. Paul has recovered and sold a number of important blues in the past, including a 39.34 carat blue diamond.

Pink diamonds are one of the most highly coveted of all the fancy colours and have only been found in a handful of mines throughout the world. The pink colour is thought to be brought about by an alteration to the diamonds’ molecular structure, possibly caused by a seismic shock at the time of its formation. To date, it remains the highest price per carat (approximately $5 million) achieved for a diamond sold at auction in 2022.

Yellow diamonds have long been valued and prized but they were only discovered sporadically until the late 1860s in the Cape Province in South Africa, where their relative abundance prompted the name ‘cape stones’ – a term that continues in usage today. The yellow hue is due to the presence of nitrogen within the crystal structure, where a carbon atom is replaced by nitrogen. Paul produces yellow diamonds from all of its operations.

Champagne diamonds are light brown in colour, whereas cognac diamonds have a more orange-brown hue. Champagne/cognac diamonds have a vast range of tones, ranging from very light to very dark, often with modifying colours, such as hints of orange, red or yellow. The largest faceted diamond on record, the 545 carat Golden Jubilee, is golden brown and was polished from a huge stone recovered in 1986. Paul produces a regular supply of champagne diamonds.

Pure orange diamonds are incredibly rare and therefore highly coveted by collectors. The orange tone is usually caused either by the presence of nitrogen or by an absorption band centred at approximately 480 nm.

Natural green diamonds are exceptionally rare, second only to red diamonds in their rarity. They are believed to owe their colour to millions of years of exposure to radioactivity, emitted by uranium compounds. The vast majority of green diamonds are only green in their rough form, with stains or coatings on the surface of the stone, which tend to be lost in the cutting process – these are known as ‘faceted’.

Although all natural fancy coloured diamonds are extremely rare, none are more so than the red diamond. Only 20 to 30 true red diamonds are known to exist and most are less than half a carat in size. Unlike other fancy colour diamonds that derive their colour from impurities, red diamonds are made purely from carbon, just like colourless diamonds. Due to their incredible rarity, red diamonds hardly ever come to market, but in November 2014 a heart-shaped 2.09 carat red diamond ring sold for US$5.09 million.