Cut registry › Jewellery cuts › Heart
Jewellery cuts · Fancy brilliant
The hardest outline to cut well.
A heart is the only shape here that most people choose for what it means rather than for how it performs. That is a perfectly good reason, and it is still worth knowing what it costs.
The short version
A heart shaped diamond is a brilliant cut with two rounded lobes separated by a cleft at the top and a single point opposite, typically carrying 56 to 58 facets.
It is the most difficult common outline to cut well, because the eye has two halves to compare and notices immediately when they do not match.
Definition
A heart is closely related to a pear. Both are brilliants with a rounded end and a point. The heart adds the cleft, and the cleft is where all the difficulty lives: it must be sharp, it must sit exactly on the centre line, and the point at the opposite end must sit directly below it.
Three checks catch nearly every badly cut heart, and none of them needs equipment. The two lobes should be the same size and the same roundness. The cleft between them should be well-defined and dead centre. The point should line up straight below the cleft. Asymmetry shows more here than in any other shape in production.
Size is the other constraint, and it is unusually specific. Below about 0.50 carats the outline stops reading once prongs are on it. A heart comes into its own from roughly 0.75 carats, and clearly at a carat and above. This is one of the few cases where a hard minimum is honest advice rather than an upsell.
Proportions
Commonly cited ranges against our measured reference stone. On a heart, ratio controls whether the outline reads as a heart at all, which makes it more consequential than on most shapes.
| Measure | Commonly cited | Our reference stone | What it does |
|---|---|---|---|
| Length-to-width | 0.90 to 1.10 | 1.00 | Wider reads squat; narrower starts to read as a pear. |
| Depth | 56% to 66% | 66.8% | Hearts carry weight in the pavilion, so face-up size lags the carat. |
| Table | 53% to 65% | 56.2% | The flat top, as a share of the width. |
| Pavilion angle | not commonly published | 46.4° | Decides whether light returns or escapes. |
| Facets | 56 to 58 | 62 | Counted as facets that actually reach the surface. |
GIA issues no cut-quality grade for heart shapes. The symmetry grade is the one to read, and on this shape it is doing more work than on any other. Buy on face-up millimetres rather than carat weight, because a heart hides more of its weight in the pavilion than most shapes do.
Light
Measured on the census that runs on every cut on this site: 3,200 rays face-up, 2,200 at 20° tilt, on exact facet geometry, against T57 as the standard.
| Material | Useful light | Leak | Fire | Scintillation | Global | vs the standard |
|---|---|---|---|---|---|---|
| Diamond | 46.65% | 32.47% | 83.80 | 74.79 | 62.85 | −25.75 |
| Moissanite | 43.63% | 31.88% | 92.61 | 74.79 | 63.65 | −26.17 |
| Cubic zirconia | 54.58% | 31.15% | 90.75 | 74.79 | 67.07 | −24.70 |
| T57 standard, diamond | 92.28% | 1.88% | 78.85 | 71.82 | 88.61 | 0.00 |
Our reference heart returns 46.65% of entering light usefully and leaks 32.47%, for 62.85 Global against the standard’s 88.61. That is the lowest Global of the brilliant-cut jewellery shapes we measure.
We would rather say that plainly than dress it up. A heart is a complicated outline with a cleft in the middle of it, and complicated outlines lose light. Anyone choosing a heart is choosing it for what it is, and they are owed the number rather than a compliment.
It carries 62 active facets for 74.79 on scintillation, above the round brilliant’s 71.82, and its fire reads 83.80. So a well-cut heart does not look dull. It throws plenty of flashes. It simply sends a smaller share of the light back to you than a rounder shape would.
Two figures on this page are deliberately absent. We do not publish an Index symmetry score for the heart, because our symmetry axis measures facet regularity within each pavilion family and a heart’s pavilion is irregular by design, so the number carries no information. And its tilt figure sits at the scale ceiling for the same reason the radiant’s does: on a stone with a low face-up baseline, holding what little there is under tilt is not stability.
Against the standard
Light return. 92.28% for the round against 46.65% for the heart, a Global gap of 25.75 points. This is the largest gap of any brilliant-cut shape on this page.
Sparkle character. 62 facets against 57, so 74.79 on scintillation against 71.82. A heart produces more separate flashes than a round; it returns less of the light overall.
Face-up size. A heart usually reads smaller for its carat weight than a round, because more of its weight sits in the pavilion. Compare millimetres.
Durability. The point needs a V-prong or a bezel, exactly as a pear’s does. The cleft is not a weak point structurally, though it is a place dirt collects.
Price. Generally less per carat than a comparable round, though well-cut hearts in larger sizes are genuinely scarce and priced accordingly.
The baseline for all of this is the round brilliant itself. Its facet plan is set out in the anatomy of a round brilliant, and the measured standard we compare against is T57, the stone Tolkowsky published in 1919.
Materials
In moissanite the heart returns 43.63% for 63.65 Global, with fire at 92.61 against 83.80 in diamond. On a shape whose light return is already modest, moissanite’s extra dispersion is a reasonable trade: you gain in colour what you were not getting in white light anyway.
In cubic zirconia it returns 54.58% for 67.07 Global, its best showing of the three.
Compare all three for this shape in the Index.
Trade-offs
Questions
The questions buyers actually ask, answered in full. Where the answer is ours to prove, the figure is measured on the Index; where it is an established gemological fact, it is stated as one.
A heart shaped diamond is a brilliant cut with two rounded lobes separated by a cleft and a single point opposite them, typically carrying 56 to 58 facets. It is closely related to the pear, with the cleft as the difference and the difficulty.
Three checks, all of them possible with the naked eye. The two lobes should match each other in size and in roundness. The cleft should be sharp and sit exactly on the centre line. The point should line up directly below the cleft. Asymmetry is more visible in a heart than in any other shape, because the eye has two halves to compare.
Below roughly 0.50 carats the outline stops reading clearly once the stone is set and prongs cover part of it. A heart shows its shape properly from about 0.75 carats, and comes fully into its own at a carat and above. This is a genuine constraint of the outline rather than a sales argument.
Between 0.90 and 1.10, with 1.00 giving the classic balanced outline. Wider than that and the heart reads squat; narrower and it starts to look like a pear with a notch in it. Our reference heart sits at 1.00.
Yes, with the point protected by a V-prong or a bezel, exactly as a pear requires. The cleft is not structurally weak, although it is a place where dirt collects and it benefits from regular cleaning.
No. GIA issues cut grades for round brilliants only. On a heart the symmetry grade is the most informative part of the report, because symmetry is the property this shape is most often let down by.
They throw more separate flashes and return less light. Our reference heart carries 62 facets against the round brilliant’s 57, scoring 74.79 on scintillation against 71.82, but it returns 46.65% of entering light against 92.28%. That is the lowest light return of the brilliant-cut shapes we measure, and it is a property of a complicated outline rather than of any one stone.
Per carat, generally yes. The exception is well-cut hearts at larger sizes, which are genuinely scarce because the shape is difficult, and which are priced accordingly.
Often. A heart carries more of its weight in the pavilion than most shapes, so face-up size lags the carat figure. Compare millimetres across the widest part of the stone rather than comparing weights.
They belong to the same family: a brilliant with a rounded end and a point. The heart divides the rounded end into two lobes with a cleft between them, and that cleft is what makes the shape difficult to cut and easy to get wrong.
Next
See the whole set on the jewellery cuts index, or the measured house and historic cuts in the cut registry.
Method
Monte-Carlo on exact facet geometry: 3,200 rays face-up plus 2,200 at 20° tilt, cosine-weighted from a 7° near-vertical cone. Useful light is what exits through the crown within 64° of vertical. The same protocol runs on every cut on this site, so the figures are comparable to each other.
They measure our reference geometry for the shape at the proportions listed above, not an average of stones on the market. A heart cut to different proportions will read differently. Treat them as a like-for-like comparison between shapes, not as a grade for any individual stone.
Engine estimates, ±2 points, not lab-certified grades. We do not publish the Index symmetry axis on these pages: it scores facet regularity within each pavilion family, which is meaningful for a round brilliant and misleading for a shape whose pavilion is deliberately irregular.
74.79 here against the standard’s 71.82. The term is 100(1−e−n/45) on the count of facets that actually reach the surface, so it is a pure function of facet count and nothing else.