The heart-cut diamond is a fancy-shape brilliant in which the outline of the stone is fashioned to resemble a symmetrical heart: two rounded lobes meeting at the top in a distinct cleft, tapering to a single point at the base. Most heart-cut diamonds carry between 56 and 58 facets arranged in a modified brilliant pattern derived from the round brilliant, though some cutters employ additional break or girdle facets to improve light return in the lobes. The shape is among the most technically demanding of all fancy cuts, requiring the cutter to produce two lobes of equal size and curvature, a clean, well-defined cleft, and a straight, centred point — all while preserving as much carat weight from the rough as the geometry allows. Because of this complexity, heart-cut diamonds represent a small fraction of total diamond production and command a modest premium in cutting labour relative to simpler fancy shapes.

History and Development

Heart-shaped gemstones have appeared in European jewellery since at least the sixteenth century, when table-cut and early faceted stones were occasionally shaped to convey romantic or devotional symbolism. The form became more technically refined as lapidary tools improved through the seventeenth and eighteenth centuries. The modern heart cut, with its full brilliant-style facet arrangement, emerged alongside the development of the round brilliant in the late nineteenth and early twentieth centuries, as diamond cutters in Antwerp and Amsterdam began applying precise angular calculations to fancy outlines. By the mid-twentieth century the heart cut had become a recognised commercial shape, catalogued alongside the pear, marquise, and oval as one of the principal fancy brilliant forms. Its association with romantic sentiment has kept it in continuous demand, particularly for engagement rings and anniversary jewellery, though it has never approached the market share of the round brilliant or the princess cut.

Cutting and Proportions

Producing a well-proportioned heart cut begins with rough selection. The cutter seeks a piece of rough whose natural shape — often a macle (a twinned octahedral crystal) or a suitably oriented fragment — allows the heart outline to be mapped with minimal loss. The yield from rough to polished is typically lower than for a round brilliant cut from comparable material, which contributes to the shape's relative scarcity and slightly elevated per-carat price compared with other fancy shapes of equivalent quality.

The critical proportions governing the appearance of a finished heart-cut diamond are as follows:

• Length-to-width ratio: The most widely recommended range is 0.90 to 1.10, with a ratio close to 1.00 producing a stone that appears as wide as it is long — the classic, compact heart silhouette. Ratios below 0.90 yield a wide, squat appearance; ratios above 1.10 produce a narrow, elongated form that many observers find less immediately legible as a heart shape.
• Lobe symmetry: The two upper lobes must be mirror images of one another in both curvature and size. Any asymmetry is immediately apparent to the eye and is considered a significant cutting fault. Grading laboratories including the Gemological Institute of America (GIA) assess symmetry in fancy shapes as part of their polish and symmetry grades.
• Cleft definition: The cleft — the inward V-shaped notch at the top of the stone — should be sharp and centred. A shallow or off-centre cleft undermines the legibility of the heart outline, particularly when the stone is set in a bezel or channel setting that partially obscures the girdle.
• Point integrity: The lower point is structurally vulnerable and is typically protected in setting by a V-prong or claw specifically shaped to cradle it. A chipped or abraded point is a common condition issue in pre-owned heart-cut diamonds.
• Table percentage and depth: As with round brilliants, excessively deep or shallow pavilions produce light leakage. Most well-cut heart diamonds fall within a table percentage of roughly 53–63 per cent and a total depth of approximately 56–62 per cent, though these ranges are guidelines rather than fixed standards, and the interaction of all proportions determines actual optical performance.

Optical Performance and the Bow-Tie Effect

Because the heart cut is derived from the brilliant facet arrangement, a well-proportioned stone can achieve strong brilliance and fire. However, like most elongated or irregular fancy shapes — the pear and marquise in particular — heart-cut diamonds are susceptible to the bow-tie effect: a darkened zone across the centre of the stone, roughly corresponding to the observer's own shadow falling across the table facet. The severity of the bow-tie depends on the pavilion angle, the width of the stone relative to its depth, and the precision of the facet layout. A faint bow-tie is considered acceptable by most trade standards and is nearly universal in the shape; a pronounced, opaque bow-tie is regarded as a cutting deficiency and depresses value. No standardised grading scale for bow-tie severity exists across all laboratories, so buyers are advised to examine stones in person or request video documentation under varied lighting conditions.

The hearts and arrows optical phenomenon, familiar from ideal-cut round brilliants, can in principle be produced in heart-cut diamonds when facet angles and alignments are held to very tight tolerances, though this is far less commonly marketed or certified in heart shapes than in rounds.

Colour and Clarity Considerations

The heart cut's relatively large table facet and open crown facets mean that body colour is somewhat more visible than in a round brilliant of equivalent colour grade. Buyers sensitive to warmth in near-colourless stones often find that a heart cut appears one colour grade warmer in face-up view than a round brilliant of the same GIA colour grade. For this reason, many trade professionals recommend selecting a heart-cut diamond one grade higher in colour than one might choose in a round brilliant for the same setting metal — particularly in white gold or platinum, where yellow or brown tints are most apparent.

Clarity inclusions positioned near the point or along the cleft are of particular concern: the point is a stress concentration and any inclusion in that region increases the risk of chipping, while inclusions near the cleft may be visible and difficult to conceal under a prong. Eye-clean stones in the VS2 to SI1 range are generally achievable at reasonable cost, and the facet arrangement does offer some capacity to mask inclusions that fall beneath crown facets away from the table.

Setting and Jewellery Context

The heart cut is most frequently encountered in solitaire engagement rings, pendants, and stud earrings. In ring settings, the stone is almost universally oriented with the point directed toward the wearer's fingertip, so that the cleft and lobes face the observer. A three-prong setting — two prongs cradling the lobes and one V-prong protecting the point — is the most practical configuration, though bezel settings and halo designs are also used. In pendant and necklace applications, the stone is typically suspended from a bail attached at the cleft, displaying the full heart silhouette face-forward.

Matched pairs of heart-cut diamonds, used in earrings or as side stones, require particularly careful selection for lobe symmetry and outline consistency, as any divergence between the two stones is immediately apparent when worn side by side.

Market Position

Heart-cut diamonds occupy a niche but stable position in the fancy-shape market. They are purchased overwhelmingly for their symbolic resonance rather than for optical efficiency or fashionable geometry, and their buyers tend to be less price-sensitive to shape premiums than buyers of more commercially dominant cuts. The shape is not subject to the same cyclical fashion pressures as the cushion or oval cuts, whose market shares have fluctuated substantially over the past two decades. Prices per carat for heart-cut diamonds of equivalent quality to round brilliants are generally lower, reflecting reduced consumer demand and the difficulty of reselling the shape on the secondary market, though the cutting premium partially offsets this discount at the rough-to-polished stage. GIA issues grading reports for heart-cut diamonds that include colour, clarity, polish, and symmetry grades but do not assign an overall cut grade, as no universally accepted cut-grading standard for fancy shapes has been established by any major laboratory.

Further Reading

• GIA: Diamond Quality Factors — gia.edu
• GIA Gems & Gemology: Fancy-Shape Diamonds — gia.edu