From the hidden depths of the Earth to the refined elegance of a bespoke jewellery piece, the journey of a rare coloured diamond is nothing short of extraordinary. These captivating gems, blushed with shades of pink, blue, yellow, or green, are formed over billions of years through powerful natural forces and the presence of rare trace elements.
Unlike their colourless counterparts, coloured diamonds are formed when trace elements or structural anomalies interact with carbon atoms during the diamond’s creation deep within the Earth’s mantle. But the story doesn’t end beneath the surface. Once brought to light through the artistry of mining and the precision of cutting, a coloured diamond begins a second transformation from rough, unrefined stone to dazzling masterpiece.
From ancient geological processes to the hands of skilled artisans and jewellery connoisseurs, the path of a coloured diamond is one of wonder, rarity, and lasting value and continues to captivate the world of high end jewellery.
How are coloured diamonds formed?
Much like colourless diamonds, coloured diamonds were formed between 900 million and 3.2 billion years ago, deep below the Earth’s surface, under intense heat and extreme pressure. They, too, are made up almost entirely of carbon atoms; however, low levels of foreign atoms per million carbon atoms or structural defects can change them from colourless to coloured.
Extremely sought-after and expensive, coloured diamonds are ultra-rare gifts of nature. Incredible processes in the diamonds have allowed for the formation of a stunning array of different coloured diamonds, from subtle, simple impacts to vivid, extravagant designs.
The formation of yellow diamonds
The vibrant yellow hue seen in fancy coloured diamonds is the result of nitrogen atoms embedded within the diamond’s crystal lattice. These nitrogen atoms are arranged in such a way that they absorb light from the blue end of the spectrum, allowing the stone to reflect a rich yellow tone.
The intensity of the colour depends on the concentration of nitrogen present in the diamond’s structure, and generally, the deeper and more vivid the yellow, the greater the rarity.
Blue diamonds
The colour blue comes from the chemical element boron trapped inside the diamond.
Although blue diamonds only need a tiny amount of boron to produce their colour, they are extremely rare, with only one in 200,000 natural diamonds showing a light shade of blue and even fewer displaying a deep, rich colour.
Pink diamonds
Whilst the colour of most diamonds can be scientifically explained, the origin of pink colouration in natural diamonds still confuses some scientists.
They believe that pink diamond shades are caused by plastic deformation, in response to extreme natural stresses during the diamond’s storage deep below the surface of the Earth. This means that they didn’t actually start their growth process pink, making pink one of the rarest fancy coloured diamonds.
Green diamonds
Interestingly, a natural green diamond’s colour does not develop until the end of its journey to the Earth’s surface.
The colour comes from natural irradiation, usually caused by alpha particles.
Absorbing red and yellow light causes the diamond to reflect a green hue; however, this is usually confined to a very thin layer at the surface of the original rough diamond, so it’s very rare that the green colour will be present throughout the diamond.
Black diamonds
Black diamonds are not truly black as they contain numerous dark inclusions, meaning little light can pass through them, so this is what gives them their dark appearance. Common inclusions in black diamonds include graphite, pyrite, or hematite.
Whilst other coloured diamonds are transparent, the many inclusions in a black diamond mean it is typically opaque and will not exhibit the same fire and brilliance of a colourless or transparent coloured diamond.
Red diamonds
Red is the rarest and therefore the most expensive of all natural coloured diamonds. Red natural diamonds are so rare that only around twenty to thirty are known to exist in the entire world, and most are less than half a carat in size.
Although still uncertain, scientists believe that red diamonds get their colour the same way as pink diamonds, due to plastic deformation.
The formation of rare coloured diamond jewellery
Coloured diamonds, owing to their exceptional geological rarity and distinct trace element compositions, are highly sought after in the creation of high-end and bespoke jewellery design.
Their unique optical properties emanated from lattice defects, structural distortions, or the presence of elements such as nitrogen, boron, or hydrogen, creating a spectrum of hues including vivid yellow, intense pink, deep blue, rare green and beyond. These diamonds are meticulously selected and precision-cut to optimise colour saturation, light performance, and overall symmetry.
In luxury jewellery design, coloured diamonds are frequently employed as focal stones in unique engagement rings, high end jewellery collections, and occasion wear, where their rarity, colour grading and provenance. It begins with the careful evaluation of the rough diamond, where factors such as colour distribution, clarity, crystal orientation, and potential yield are assessed. Precision cutting is then undertaken to enhance the diamond’s natural hue and maximise brilliance, with particular attention paid to facet alignment and depth to ensure optimal light return and colour saturation.
Once the stone is cut and polished, it is integrated into a bespoke jewellery design tailored to its unique characteristics. In rings, coloured diamonds are often showcased as central solitaires or in halo settings that amplify their vibrancy. For necklaces and pendants, they may be suspended in elegant drops or geometric arrangements that draw attention to the stone’s rarity and hue and in bracelets, coloured diamonds are typically set in symmetrical patterns or interspersed with colourless diamonds to create contrast and rhythm. Earrings, whether studs, drops, or chandelier styles, are then designed to ensure balance, allowing paired stones to harmonise in both colour and brilliance.
Handcrafted rare coloured jewellery
Discover our exclusive range of yellow, pink and blue diamonds
David Morris, the Bond Street Jeweller is home to a handcrafted selection of rare coloured diamond jewellery, featuring rings,
necklaces, earrings and unique engagement rings
To view our collection, visit one of our boutiques or arrange a consultation online or in person