Diamonds come in a whole spectrum of colours: white, yellow, pink, blue, green and – rarest of all – red. Yellow diamonds were first discovered in South Africa in the 1860s, when they were termed ‘Cape diamonds’. Yellow diamonds are the most prevalent after white, comprising 60 percent of all fancy coloured diamonds. But they are still extraordinarily rare: only one in every 16,500 carats mined is a Fancy Vivid yellow diamond.
Yellow diamonds are created when nitrogen enters the stone’s chemical makeup. The majority of white diamonds contain a degree of nitrogen, which is considered an impurity. The more nitrogen, the stronger the yellow tone. On the D to Z colour scale used to grade white diamonds, colourless stones (D-F) attract the highest price tags. But diamonds with strong yellow tones, beyond Z, are considered ‘fancy’ coloured, and are graded using a separate scale, which gemmologists use to assess the saturation of colour.
The GIA’s coloured diamond grading scale ranges from Fancy Light, through Fancy, Fancy Dark, Fancy Deep, Fancy Intense to, rarest and most prized, Fancy Vivid. The way a yellow diamond is cut affects the intensity of colour; jewellers often use radiant cuts because the many facets enhance the hue. As such, emerald-cut fancy coloured diamonds are the rarest: to achieve a strong saturation without the help of facets, the colour needs to be spread evenly throughout the stone.
Saturation isn’t the only characteristic that affects a yellow diamond’s desirability. Like paint colours, yellow diamonds can have orange, brown or green tones. Preference for one tone over another is a matter of personal choice, but ‘pure’ yellow stones are the most sought-after, although more recently orangey-yellow diamonds have become highly prized.
Like white diamonds, yellow diamonds contain individual inclusions and blemishes; flawless emerald-cut Fancy Vivid yellows are true collectors’ stones.
The market for yellow diamonds has risen in the past two decades; partly due to increased interest as celebrities wear them on the red carpet, but moreover, as consumers become more aware of the beauty and rarity of these sunshine-hued stones. As jewellery connoisseurs seek to diversify, yellow diamonds represent a magnificent springboard into the exclusive world of coloured diamonds.