The 4Cs of a Diamond
Every diamond is graded on four characteristics. They are not equally important, and spending evenly across all four is the most common way to overpay for a stone that looks ordinary.
Cut — the one that matters most
Cut describes how well a diamond's facets have been proportioned and finished, not its shape. It is the only C determined entirely by human skill, and it is the one that decides whether a stone looks alive or flat.
A poorly cut stone leaks light through the bottom instead of returning it to your eye. Two diamonds of identical carat, colour, and clarity can look completely different because of it. If you have to compromise somewhere, do not compromise here.
- Excellent / Ideal — maximum brilliance; worth the premium
- Very Good — visually close to Excellent for noticeably less
- Good and below — visible loss of light return, especially in larger stones
Colour — how little you can get away with
Colour grades run from D (completely colourless) to Z (noticeably tinted). The scale measures the absence of yellow, and the differences between neighbouring grades are extremely subtle face-up.
Most people cannot tell D from G without a side-by-side comparison against a white background. Because the setting influences perception, the metal you choose should decide how far down the scale you can go.
- White gold or platinum — D to G keeps the stone reading icy
- Yellow or rose gold — H to J looks colourless in context and costs far less
- Fancy colours are graded on a separate scale, where saturation adds value rather than subtracting it
Clarity — aim for eye-clean, not flawless
Clarity grades the internal inclusions and surface blemishes formed as the crystal grew. Grading is done under 10× magnification, which is not how anyone will look at your ring.
The useful target is 'eye-clean': no inclusions visible to the naked eye at normal viewing distance. That is usually VS2 or SI1, well below the flawless grades that carry the largest premiums.
- FL / IF — flawless under magnification; a rarity premium, not a visual one
- VVS1–VS2 — eye-clean in essentially all cases
- SI1–SI2 — often eye-clean, but must be checked stone by stone
- I1 and below — inclusions typically visible without magnification
Carat — weight, not size
A carat is 0.2 grams. It measures weight rather than the dimensions you actually see, so a deep-cut stone can weigh more while looking smaller from above than a well-proportioned one.
Prices jump at the round numbers because demand does. A 0.90ct stone is materially cheaper than a 1.00ct of the same quality, and the diameter difference is roughly a third of a millimetre.
How to spend the budget
If you want one rule: buy the best cut you can, drop colour and clarity to the point where the stone is still eye-clean and looks white in its setting, and take the carat weight that is left over.
Every Forever Jewels stone lists its full grading report, and our advisors will tell you plainly when a higher grade will not be visible on the finger.
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