By Alexia Sorokina, Gemmologist | Say Yes in Paris
The first thing most people do when researching engagement rings is look up “best diamond quality.” They find the GIA grading scale, see D Flawless at the top, and assume that’s the goal. I have spent fifteen years handling diamonds. I have never once recommended D Flawless to a client — not because it isn’t beautiful, but because the difference between D and F is invisible to the human eye, and the difference in price is not.
This is what the diamond industry does not particularly want you to know.
The grading scale and where it stops mattering
The GIA grades diamond colour on a scale from D to Z. D is completely colourless. Z is light yellow. In between, the differences are subtle — and they become invisible to the naked eye long before you reach the bottom of the alphabet.
In my experience, the threshold where most people stop perceiving colour is somewhere around G or H. An F diamond and a D diamond, placed side by side on a white surface, will look different to a trained eye under controlled lighting. On a hand, in daylight, at a dinner table — they are indistinguishable.
The same is true of clarity. The GIA clarity scale runs from Flawless down through Internally Flawless, VVS1, VVS2, VS1, VS2, SI1, SI2, and I grades. Above VS1, inclusions are not visible to the naked eye. They are not even visible to most jewellers’ loupes without effort. An Internally Flawless diamond and a VS1 diamond are, on the hand, identical.
The price difference between them is not identical at all.
What F VS1 actually is
F VS1 is where I always begin with clients who come to me without a fixed idea. It is the sweet spot — the point where you have exceptional quality in both colour and clarity, where the stone is genuinely, visibly beautiful, and where you are not paying a premium for characteristics that exist only on a certificate.
An F colour diamond is near-colourless. On a hand, it reads as white. It faces up beautifully in platinum or white gold, and it holds warmth well in yellow gold. VS1 clarity means the inclusions are minor, visible only under 10x magnification, and entirely irrelevant to how the stone looks or performs.
Between D and F, you may lose 20 to 40 percent of the purchase price. Between IF and VS1, the saving is often similar. Combined, you have a substantial sum to redirect — towards carat weight, towards a more interesting cut, towards a better setting, or simply towards not overpaying.
The case for spending less on grade and more on character
There is something the grading scale cannot measure: the way a diamond moves. The way it catches light at an unexpected angle, holds warmth in the evening, changes completely when it leaves a showroom and enters the world.
The stones I find most beautiful are rarely at the top of the GIA scale. They are often F or G in colour — warm enough to have life, colourless enough to read as white. They are VS1 or occasionally VS2 in clarity. And they are sometimes old mine cuts or old European cuts, which were made before modern grading existed and have a character that no certificate can quantify.
If you take the budget you would have spent on D Flawless and apply it to a larger F VS1, or to an antique cut with genuine personality, or to a metal and setting that truly suits the stone — you will almost certainly end up with a ring you love more.
One thing to look for on the certificate
When you are given a GIA certificate, check the fluorescence field. Strong blue fluorescence in an F-H colour diamond is something the market penalises — and something I consider an asset. Under ultraviolet light, the stone glows blue. In daylight, which contains UV rays, this can make a near-colourless stone appear even whiter. The price is lower. The appearance, in the conditions where the ring will actually be worn, is often better.
This is not a secret. It is simply information the industry has not gone out of its way to share.
What this means in practice
If you come to see me with a budget and a goal of buying the best diamond possible, I will not take you to the D Flawless stones first. I will take you to the F VS1 stones — and I will show you where the money goes when it isn’t spent on invisible differences.
I will also show you the fluorescent stones. And the antique cuts. And whatever else makes sense for the ring you are trying to create and the person who will wear it.
A diamond certificate is a document. What you are buying is a stone. They are related, but they are not the same thing.
Alexia Sorokina is a gemmologist and jeweller with fifteen years of experience in natural diamonds. She is the founder of Say Yes in Paris, a bespoke engagement ring atelier and proposal concierge based in Paris.