Red Diamond, the World's Most Precious Gemstone

By Sotheby's

I t’s easy to recognise a diamond. Walk along London’s world famous Bond Street, home of the most influential jewellers, and one is instantly mesmerised by rare diamonds in colours ranging from whites and yellows to pinks and even the occasional blue glimmering in a shop window. Could any other diamond be rarer than this offering? The answer is yes. Red diamonds take rarity to an entirely new level. Leading the upcoming online-only auction Jewels Online: Part II is just such a rare find – a ring featuring a 0.19 carat Fancy Red diamond encircled in white and pink diamonds.

Not widely known or recognised, red diamonds are an enigma. Considered the world’s most precious gemstone, they are scarcely available on the diamond market, and only 30 natural red diamonds are known to exist in the world. Their rarity is dictated by nature. The unique composition of chemical elements found within these gemstones governs their colour, value, and ultimately, desirability.

What makes a diamond red? This is actually an impossible question to answer, as there is no impurity that causes its colour, only the evidence that these diamonds have a mutation within their crystal lattice that alters the stone’s molecular structure. Red diamonds exist in only one colour intensity – Fancy – although their clarities range from Flawless to Included, just as other coloured diamonds.


A pure Fancy Red diamond with no undertones or secondary hues of purple, pink, orange or brown is the most valuable and desirable. This rich red colour is appealing not only for its rarity but also for its meaning all over the world. In China, red is the most auspicious colour symbolising luck; in India it symbolises purity; and universally red is the colour of love. It is difficult to find red diamonds in sizes over 1 carat. The largest red diamond that is known today is the Red Moussaieff Diamond, weighing 5.11 carats, Fancy Red and Internally Flawless.

Very few people will ever see much less handle a red diamond in their lifetime. Its mystifying anatomy make it one of nature’s most magical anomalies. In Sotheby’s Jewels Online: Part II online-only auction, a vibrant 0.19 carat Fancy Red diamond is encircled in white and pink diamonds at an estimated £50,000-70,000 just in time for celebrating Valentine’s Day or Chinese New Year.

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