Diamond guide
Understanding the 4 Cs
Carat, cut, colour and clarity are what a diamond's certificate grades — and what actually determines how a stone looks and what it costs. Here's what each one means in plain English.
01
Carat
A unit of weight, not size — 0.2 grams per carat. Two stones of the same carat weight can look different sizes depending on how they're cut, so weight alone doesn't tell you how big a diamond looks on the hand.
02
Cut
How well a stone's proportions and facets are cut — this is what actually controls sparkle. A well-cut diamond returns more light to the eye, so cut affects brilliance more than colour or clarity do.
03
Colour
Graded D (colourless) to Z (noticeably tinted) on the GIA scale. Most people can't tell the difference by eye past G–H, which is why near-colourless stones are usually the best value.
04
Clarity
Measures internal and surface inclusions, from Flawless down to I3. Most inclusions are microscopic — an "eye-clean" stone (typically VS–SI) looks perfect to the naked eye at a fraction of the price of Flawless.
Why certification matters
Every diamond here is independently graded by GIA or IGI, the two most trusted labs in the trade. The certificate is a second, impartial opinion on the 4 Cs above — so you're never just taking our word for it.
More on this in the journal.