Shield Cut Diamond Guide: Facets, Ratio, Settings and Price

What is a shield cut diamond?

A shield cut diamond is a geometric fancy shape with an outline like a heraldic shield. Most have five or six sides: a straight or slightly curved top edge, two short shoulders at the upper corners, and two longer flanks that angle inwards to a point at the base. It is not a standardised shape. Each cutter's version differs a little, and many shields are cut to order from rough crystal that suits the outline. It sits in the same family as the other shapes in our guide to shield, kite, hexagon and other geometric cuts.

You will mostly see shields as shield cut side stones: a matched pair either side of a round, oval, emerald or cushion centre. Their straight top edge sits neatly against the centre stone and the point leads the eye out along the band. They belong with the trapezoids, half moons and bullets covered in our page on side stone cuts that flank a centre diamond. Larger shields also appear as centre stones, in Art Deco-style rings, men's rings and pendants.

The shape inherits the properties of diamond itself: 10 on the Mohs hardness scale and a refractive index of about 2.42, which is what bends and returns light so strongly. Hardness is not the same as toughness, though. Diamond can chip along its cleavage planes (natural planes of weakness in the crystal) if a thin edge takes a knock, and a shield has a point and four or five corners. Protecting them shapes most of the advice below.

To see where the shield fits among every other shape, our comparison of all 34 diamond cuts lays them out side by side. Any term you have not met before is explained in our plain-English jewellery glossary.

What facet patterns does a shield cut use?

Shields are cut in two main styles, and the choice changes how the stone looks far more than the outline does.

A step cut uses long, parallel facets arranged in rows that step down from the girdle (the outer edge) like stairs, the same principle as the baguette's step-cut faceting. It gives broad flashes of light and dark, often called a hall-of-mirrors effect, and a calm, architectural look. Step-cut shields are the usual choice for side stones, especially beside an emerald or Asscher centre.

A brilliant (or modified brilliant) shield uses triangular and kite-shaped facets, which break light into many small, quick sparkles called scintillation. Brilliant shields suit centre stones and pair well with round, oval and cushion centres. A few antique-inspired shields are cut with a domed, flat-based pattern instead; our page on how brilliant faceting differs from a rose cut explains that older style.

Grading reports describe the shape and cutting style together, for example a shield step cut or a shield modified brilliant. GIA does not give fancy shapes an overall cut grade the way it does for round brilliants, but polish and symmetry are still graded, and those two grades are worth reading closely.

What is the ideal ratio for a shield cut diamond?

The length-to-width ratio compares how long the stone is, from the top edge to the point, with how wide it is across the shoulders. Divide the length by the width on the report. A ratio of 1.00 means the shield is exactly as long as it is wide. There is no industry standard, but most shields sit between about 0.85 and 1.20.

Once a shield goes much past 1.20, it starts to resemble the long, pointed bullet cut, so decide which look you actually want before comparing stones.

Depth and table (the large flat top facet) vary widely between cutters, so judge the stone by how it looks rather than chasing one number. As a rough guide, many shields sit at a total depth of about 60–72%. Much deeper and the stone carries hidden weight underneath and faces up small; much shallower and it can show a window, a washed-out area in the middle where light passes straight through instead of bouncing back to your eye. In step-cut shields, a window is easy to spot as a glassy patch.

For side stones, matching matters more than the exact ratio. A pair should be close in length, width and depth, usually within about 0.1–0.2 mm, and close in colour and clarity, so the ring looks balanced from both sides. Cutters often cut pairs from the same rough or in the same session for this reason.

How big should a shield cut diamond be?

Because the point and angled flanks trim away area, a shield faces up a little smaller than a square of the same width. The figures below are typical for a shield around 1.00 in ratio at a moderate depth. Real stones vary with depth, so always compare millimetres rather than carat weight alone.

For a three-stone ring, side stones usually measure about 60–70% of the centre's width. Beside a 1 carat round (about 6.4 mm across), that means shields of roughly 4.0–4.5 mm, about 0.25–0.35 carat each. Go smaller and the shields read as accents; go larger and they compete with the centre.

As a centre stone, a shield reads clearly from about 0.70 carat up. Below that, the shoulders and point are small enough that claws can blur the outline, although a bezel keeps the shape crisp even in smaller sizes.

What colour and clarity should a shield cut diamond have?

Shields tend to show body colour at the point, where light paths through the stone are longer and colour concentrates, and step-cut shields show colour more than brilliants overall. For a centre stone in white gold or platinum, most people are happy from G–H colour. In yellow or rose gold, I or J can look white, because the warm metal masks a slight tint.

Side stones should match the centre within about one colour grade. A shield pair that is noticeably warmer or whiter than the centre is the most common reason a three-stone ring looks slightly off, even when every stone is well cut.

Clarity depends on the cutting style. A step cut's open, mirror-like facets act like a window into the stone, so inclusions (internal features) are easy to see. Aim for VS2 or better in a step-cut shield, and VS1 for larger step-cut centres. Brilliant shields hide small inclusions better, so a carefully chosen eye-clean SI1 (no inclusions visible without magnification at normal viewing distance) can work. Wherever the stone, avoid feathers (small internal cracks) near the point or corners, as they can weaken the thinnest areas.

• Step-cut shield, white metal: G–H colour, VS2 or better.
• Brilliant shield, white metal: G–H colour, VS2–SI1 eye-clean.
• Yellow or rose gold: I–J colour can look white.
• Side-stone pairs: within one colour grade of the centre and of each other.
• Avoid: feathers or chips at the point and shoulders.

What is the best setting for a shield cut diamond ring?

The point and corners are the most exposed parts of a shield, so the setting's first job is to cover them. The common options for a shield cut diamond ring:

• Three-stone with shield side stones: the straight top edge sits against the centre and the point faces out towards the band. It works with round, oval, emerald, cushion and princess cut centre stones, and the shields often share a claw with the centre.
• Claws: a claw at each shoulder plus a V-claw (a V-shaped claw) wrapping the point. Most shields need four to six claws in total.
• Bezel or half-bezel: a thin rim of metal around the edge. It protects the point and every corner, keeps the geometric outline crisp and suits a shield centre stone.
• Shield centre solitaire: usually worn point towards the wrist, like a crest, though point towards the fingertip gives a longer look.
• Men's and signet-style rings: a shield set flush or in a bezel suits a heavier band.
• Pendants and earrings: a shield hangs naturally point-down from a bail or stud.

Which wedding band suits a shield cut diamond ring?

A three-stone ring with shield side stones is wide across the shoulders, and the points of the shields reach down towards the finger. A straight wedding band will only sit flush if the head of the ring is raised above the band line. Otherwise there is a small gap, which some people like and others do not.

If you want the band to sit tight against the ring, the usual answers are a contoured band, shaped to follow the outline of the stones, or a notched band with a small cut-out where the points sit. For a shield centre worn point-down, a V-shaped or chevron band echoes the point and frames it. Plain bands in the same metal keep the geometric look clean; a row of small step-cut diamonds suits step-cut shields.

Plan the band at the same time as the engagement ring. A contoured band is far easier to make well when the jeweller has the original ring and its exact measurements.

How does a shield compare with trilliant, trapezoid and other side stones?

The shield vs trilliant diamond question comes up most often. Both lead the eye outwards, but trilliant triangles have three points to protect and usually a brilliant pattern, while a shield has one point and a straight top edge that sits more cleanly against a square or rectangular centre. Next to an emerald cut, trapezoid side stones give a similar flat-edged line without any point at all. For round and oval centres, half moon pairs that hug a round or oval follow the curve more closely.

Among the geometric shapes, a five-sided shield overlaps with five-sided pentagonal cuts, and a six-sided shield shares the angular lines of the hexagonal diamond outline. The four-sided kite cut and the rhombus-shaped lozenge are the other angular choices for centre stones. To see how all of these relate to the classic shapes, start with our overview of how diamond shapes differ.

How much does a shield cut diamond cost in Australia?

Shields are cut from both natural and laboratory-grown diamond, and the two look identical to the eye. Lab-grown diamonds are real diamond, grown in a laboratory rather than mined; they cost much less and are easier to find in matched pairs and larger sizes. Natural shields are rarer. Both should come with an independent grading report, from a lab such as GIA or IGI, that states whether the stone is natural or lab-grown.

Because few cutters make shields and many are cut to order, availability varies more than price. Side stones are usually sold and priced as a matched pair, and a well-matched pair costs more than two similar single stones because of the extra rough and time needed to match them. Per carat, a single shield is usually priced below a round of the same weight, colour and clarity.

These are broad ranges only; prices move with the market and with the exact grades, matching and cutting quality. What moves a shield's price most is carat, colour, clarity, how closely a pair matches and how crisp the outline is.

How do you choose a shield cut diamond? Step by step

1. Read the report. Confirm the shape and cutting style (step or brilliant), measurements, colour, clarity, polish and symmetry, and whether the diamond is natural or lab-grown.
2. Work out the ratio. Divide length by width; about 0.85–1.00 suits most side stones and 1.00–1.15 suits most centres.
3. Check the outline by eye. Even shoulders, straight flanks and a point centred below the top edge.
4. Watch a 360° video. Look for a window in the middle and for inclusions near the point or corners, especially in a step cut.
5. Match pairs carefully. For side stones, compare both stones' millimetres, depth and colour, and check they suit the centre's width.
6. Plan the setting and band together. Make sure the point is protected by a V-claw or bezel, and decide whether you need a contoured or notched wedding band.