Understanding the 4Cs

The 4Cs are how every diamond in the world is graded. Understanding them is not about becoming a gemmologist overnight — it is about being able to ask the right questions, and to know what you are looking at when a stone is placed in front of you.

Cut

Cut is the most important of the 4Cs, and the one most often misunderstood. It does not refer to the shape of the stone — round, oval, emerald — but to how well its facets have been proportioned and finished. A well-cut diamond catches and returns light from every angle. A poorly cut stone of the same colour and clarity can look lifeless, no matter the carat.

For brilliant cuts, we recommend Excellent or Very Good cut grades. For step cuts such as emerald or asscher, the precision of the lines matters more than the GIA grade alone — a piece worth holding in person to assess.

Colour

Diamonds are graded on a scale from D (completely colourless) to Z (light yellow). The differences between adjacent grades are subtle, especially once a stone is set. D, E and F are colourless. G, H, I and J are near-colourless, and they offer excellent value — the difference is rarely visible to an untrained eye, particularly in yellow or rose gold settings.

If your setting is platinum or white gold and you want a diamond that reads as truly colourless face-up, F or G is usually the sweet spot.

Clarity

Clarity describes the natural inclusions formed inside the stone as it grew. Most are invisible without magnification. The grades, from cleanest to most included, are FL, IF, VVS1, VVS2, VS1, VS2, SI1, SI2, I1, I2, I3.

For most pieces, VS1 to SI1 is the practical range. Above VS1, you are paying for clarity that no one will see without a loupe. Below SI1, inclusions can begin to interrupt the stone's brilliance.

Carat

Carat is a measure of weight, not size. A 1.00ct round diamond is roughly 6.5mm across. Two diamonds of the same carat weight can look very different depending on how they are cut — a deeply cut stone will appear smaller face-up than a well-proportioned one, even at the same weight.

Round numbers (1.00ct, 1.50ct, 2.00ct) carry a price premium. A 0.95ct stone of the same grades will look almost identical and cost noticeably less.

How we'd think about it

If you are buying a diamond and have a fixed budget, our advice is almost always the same: prioritise cut first, then colour to a level that suits your setting, then clarity to the eye-clean threshold, then size last. The result is a stone that looks bright and alive — which is what you actually notice when you wear it.

Every diamond we set is GIA or IGI certified, with the report reviewed by a gemmologist before it reaches our workshop. Book a consultation to see stones in person and find the one that feels right.