The 4 C's of Diamonds: Colour
Diamond colour is one of the four key factors that determines a diamond's quality, rarity, and price - alongside cut, clarity, and carat. But the term is a little counterintuitive: diamond colour actually measures the absence of colour. The closer a diamond is to being completely colourless, the rarer and more valuable it is.
How Diamond Colour Is Graded
Diamonds are graded on an internationally recognised scale developed by the Gemological Institute of America (GIA), running from D (perfectly colourless) to Z (visibly tinted yellow or brown). Each grade represents a small but measurable difference that a trained gemologist can detect under controlled lighting and magnification.
At EC One, we work with G colour and above - a standard that ensures every diamond we offer appears bright white to the naked eye and holds its beauty over time.
What Each Colour Grade Means
D–F - Colourless The rarest and most prized category. No colour is detectable even under 10x magnification by an expert gemologist. These diamonds have an icy, pure white appearance and command a significant premium.
G–J - Near Colourless Colour is only detectable under magnification when compared directly to a higher grade stone. To the naked eye - especially once set in a ring - these diamonds appear white. G and H in particular represent outstanding value and are the most popular choice among EC One clients.
K–M - Faint A very subtle warmth begins to appear, though most people would not notice it without a comparison stone. Faint colour diamonds can look beautiful in yellow or rose gold settings, where the warm tones complement rather than contrast.
N–R - Very Light A noticeable warmth that is visible without magnification in most lighting conditions. Best suited to antique or vintage-inspired settings in warm metals.
S–Z - Light A clearly visible yellow or brown tint. Rarely selected for fine jewellery unless the stone possesses exceptional qualities in cut or clarity.
EC One's Top Tip: Which Colour Grade Should You Choose?
The majority of our clients choose G or H colour - and it is the grade range we most often recommend. Once a diamond is set in an engagement ring or wedding band, it becomes almost impossible to distinguish a G from a D with the naked eye, yet the price difference can be substantial.
Setting metal makes a meaningful difference too. Platinum and white gold reflect colourless light back through the stone, making any trace of warmth more noticeable. Yellow and rose gold naturally complement a slightly warmer diamond, which means you can comfortably choose an I or J colour without any visible compromise - and redirect the saving towards a better cut or larger carat weight.
Fancy Coloured Diamonds
Not all colour in a diamond is a flaw. Fancy coloured diamonds - those with a strong, saturated hue such as vivid yellow, pink, blue, or green - are graded on an entirely separate scale and are among the rarest gemstones on earth. Their value increases with the intensity and evenness of their colour, the inverse of the white diamond scale.
The colour in these stones comes from specific trace elements or structural variations within the crystal:
Blue diamonds typically contain traces of boron within their crystal lattice
Fancy yellow diamonds - sometimes called canary diamonds - owe their colour to nitrogen
Pink and red diamonds are thought to result from structural distortions during formation deep within the earth, rather than chemical impurities
Champagne and Cognac Diamonds
Natural brown diamonds, commonly known as Champagne or Cognac diamonds depending on the depth of their tone, are growing steadily in popularity as a distinctive alternative to the classic white diamond. Their warm, earthy tones pair beautifully with yellow gold and offer a more affordable entry point to natural coloured diamonds with genuine character.
How EC One Sources Its Diamonds
Every diamond we offer is carefully selected to balance beauty, rarity, and ethical standards. We work with suppliers who adhere to the Kimberley Process and share our commitment to responsible sourcing - so you can wear your diamond with confidence.
Explore our diamond engagement rings →
Book an appointment to view stones in person →
