Why Fancy Shapes Don't Get a Cut Grade

A marquise report has no overall cut grade and a round one does. Why that gap exists, what polish and symmetry actually tell you, and how to judge the stone yourself.

If you compare two diamond reports, one for a round stone, one for a marquise, you will notice something missing on the second. There is no overall cut grade.

Clients often read this as an omission, or worse, as a sign the stone is inferior. It is neither.

The reason is honest

Round brilliants are standardised. The proportions that make one perform well are known, measurable and consistent, which makes it possible to grade cut on a single scale that means the same thing every time.

Fancy shapes are not standardised. A marquise can be cut long or wide, deep or shallow, with different facet arrangements, and several of those variations are legitimately beautiful. Light behaves differently in each. A single grading scale applied across all of them would produce a number that sounded authoritative and told you very little.

Rather than invent a grade that would not survive scrutiny, the report leaves it out.

What the report does tell you

Polish, how cleanly the facet surfaces were finished.

Symmetry, how precisely the facets were aligned and the outline balanced.

Both are graded, both are meaningful, and on a fancy shape they are the two craftsmanship measures you have.

The measurements are doing more work than you think

On a fancy shape, the millimetre dimensions at the top of the report are not filler. They are most of the story.

Divide the length by the width and you have the ratio, which decides whether an oval reads as a soft round or a long slender stone. Compare the depth against the width and you get a sense of how much weight is hidden below the setting rather than spread across the finger.

Two marquises of the same weight, the same colour and the same clarity can look like different jewellery. The grades will not tell you that. The measurements will.

Why the bow tie never appears on paper

Nearly every elongated brilliant shows a darker band running across its waist, where the facets return less light to the eye. The trade calls it a bow tie.

It is not graded, not measured, and not mentioned in the comments. It is a consequence of proportion, and it ranges from a faint shadow that most people never notice to a black bar that dominates the stone.

You will only ever find it by looking. This is the clearest example of why, with a fancy shape, the certificate cannot be the last word.

What you have to do yourself

Look at the stone.

Face up, at arm's length, under ordinary light rather than the spotlights over a display case. Check that the outline is even. Check that the two halves mirror each other. Check where the dark areas fall when you tilt it.

For a fancy shape, your eye is not a fallback for the certificate. It is the primary instrument, and the certificate supports it.

A short method that works

1. View it face up in normal room light. Display lighting is designed to flatter, and it flatters a poorly proportioned stone most of all.

2. Look straight down the middle. Dark and lifeless suggests too much depth. Watery and transparent suggests too little.

3. Tilt it slowly through an arc. A well-proportioned stone keeps flashing throughout. A weaker one goes flat partway.

4. Check the outline for symmetry twice, once along the long axis and once across it.

5. Compare it against another stone of the same shape. Judgement is comparative. One stone alone tells you very little, two tell you a great deal.

Where this leaves you

The absence of a cut grade is not a warning label. It is the grading laboratory declining to give you a number it cannot stand behind.

What it does mean is that buying a fancy shape sight unseen, purely on grades, is a genuinely different proposition from buying a round the same way. If you cannot see the stone, work with someone who can see it for you and who will describe what they find honestly, including the parts that are not on the paper.

Book a complimentary design consultation at our Kuala Lumpur atelier: 010-766 7448 · hq@cgarden.com.my

C'Garden is an independent bespoke jeweller in Kuala Lumpur. We are not affiliated with, endorsed by, sponsored by or certified by any organisation, laboratory or brand named in this article. Third-party names are used only to refer factually to those organisations and their published standards. All text and imagery in this article is original work created by C'Garden.

Reference

Gemological Institute of America. (n.d.). GIA diamond cut grading system. GIA 4Cs. https://4cs.gia.edu/en-us/diamond-cut/