Reflections Craft
Sign In

· 8 min read

Cushion Cut vs Princess Cut: Corners, Cost, Care

Cushion cut vs princess cut, compared by a jeweller: facet patterns, face-up size per carat, chipping risk, CAD price gaps and how to pick between them.

Both stones are square, both are brilliant faceted, and both cost less than a round of the same weight. The difference that matters is the corner: a princess has four sharp points that can chip and need protecting, while a cushion has rounded corners and no vulnerable spot. The second difference matters just as much but is harder to see on a screen, because two cushions with identical grades can throw light in completely different ways.

Two square shapes that behave differently

The Natural Diamond Council's shape glossary defines a cushion as a "square shape with rounded corners" that can be square or rectangular, and a princess as a "square cut diamond with 90-degree-angled corners". That is the whole visual difference in two lines, and everything below follows from it.

The cushion is the older shape by two centuries. The Natural Diamond Council notes it was "originally developed in the 18th century" and was once the most popular diamond shape, evolving out of the old mine cut with its squarish outline, high crown and open culet. The princess is a modern cut with no antique ancestor. If someone wants a ring that reads vintage, the cushion does that on its own; the princess never will, whatever you put around it.

The cushion's split personality

Cushions are not one product. The same certificate wording covers two quite different looks. The Natural Diamond Council describes "crushed ice" cushions as showing shimmering light in an intricate pattern, and "chunky" cushions as having a defined facet structure with larger, bolder flashes.

Crushed ice cushions sparkle constantly but in small pieces. They look busy and lively in motion and slightly hazy when still. Chunky cushions, sometimes sold as antique or old mine style, give fewer and bigger flashes with visible dark and light contrast. Neither is better. But you cannot tell which one you are buying from a grading report, only from the video, and buyers regularly order one expecting the other.

The princess is more predictable

Princess cuts vary far less. The facet pattern is consistent between stones, and the flashes tend to be linear and sharp because the outline is straight. If you like what you see in one well cut princess, you will probably like the next one. That predictability is a real advantage when you are buying online.

Face-up size for the money

Both shapes hold more of the rough crystal than a round does, so both look reasonably large for their weight. Approximate face-up measurements for well proportioned stones:

CaratPrincess, sidePrincess, corner to cornerCushion, sideRound, for reference
0.70 ct~4.9 mm~6.9 mm~4.8 mm5.75 mm
1.00 ct~5.5 mm~7.8 mm~5.4 mm6.5 mm
1.50 ct~6.3 mm~8.9 mm~6.2 mm7.4 mm
2.00 ct~6.9 mm~9.8 mm~6.8 mm8.1 mm

These vary with depth, so treat them as a guide rather than a promise. The useful number is the princess diagonal. A one carat princess measures about 7.8 mm corner to corner against 6.5 mm for a round, and because those corners sit at the widest part of the finger, a princess often reads larger than its carat weight suggests.

Cushions usually face up a fraction smaller than princess cuts at the same weight, because they tend to be cut deeper and the rounded corners remove a little surface. If maximum spread is your priority, compare millimetres on the actual stones rather than trusting the shape name.

What the report tells you, and what it leaves out

For neither shape does a GIA report carry an overall cut grade. You get polish, symmetry, measurements and proportions, which describe how well the facets were finished and aligned rather than how the stone handles light.

Other labs approach this differently, which is worth knowing before you compare two certificates. HRD Antwerp divides cut into three parts, explaining that "the Proportions determine the brilliance and the fire of a diamond", the polish defines the quality of the finish of the facets, and the symmetry describes variations in the parameters defining proportions, each graded excellent, very good, good or fair.

There is also a supplemental light performance report covering both of these shapes. The American Gem Society announced on 20 January 2023 that the AGS Ideal Report by GIA is "a digital-only supplement to GIA diamond reports" for eligible D-to-Z natural and laboratory-grown round brilliant and fancy shape diamonds, and that it covers cushion, oval, emerald, radiant, princess and fancy round brilliant. It works by tracing virtual light rays through a three-dimensional scan of the stone to measure brightness, fire and contrast.

Be clear about what this does and does not settle. Most cushions and princesses on the market do not carry that supplement. When it is absent, no document on the table tells you whether the stone is beautiful, and comparing two reports will not answer the question. Your eyes and the video have to do that work.

Colour and clarity: buy them differently

  • Cushions hold colour. The Natural Diamond Council states plainly that cushion cuts "tend to retain and show color more than round brilliant cuts" and recommends the D to G range for brightness. In practice G is the sensible floor for a cushion in platinum or white gold, and H is fine in yellow or rose.
  • Princess cuts also show a little more warmth than a round, particularly at the corners. G or H works in white metal; I is usually fine in yellow gold.
  • Clarity depends on the cushion's facet pattern. The same source notes that larger facets make inclusions more noticeable, while crushed ice patterns can better disguise them. A crushed ice cushion will often carry SI1 without anything showing. A chunky cushion wants VS2 or better.
  • Princess cuts hide inclusions moderately well, but pay attention to where they sit. An inclusion near a corner sits where the metal will cover it, and it can also be a chipping risk. One in the middle of an open table is visible and worth avoiding.
  • Fluorescence is not a problem in either shape at faint or medium. Do not pay a premium to avoid it.

If the budget is tight, drop clarity before colour on a cushion, and drop colour before clarity on a princess with a clean open table. Nobody across a table can see the difference between VS2 and SI1. They can sometimes see a warm cushion.

Corners, prongs and everyday wear

Diamond is hard but not tough, and a sharp corner is where it gives way. This is the single practical reason people choose a cushion over a princess.

  1. Insist that all four princess corners are covered by metal. V-shaped prongs that wrap each corner are the standard build. Four round prongs sitting on the corners are acceptable; prongs sitting on the flat sides are not.
  2. Check the culet and the corners under magnification before setting. A princess that already has a tiny chip at one corner will spread from there.
  3. Consider a bezel or half bezel for a princess if the wearer works with their hands. It costs a little more and removes the problem entirely.
  4. Cushions need no special protection. Four prongs is enough, and the rounded outline means nothing catches on clothing.
  5. Both shapes sit flush against a straight wedding band, which is a genuine advantage over ovals and pears. Plan the pairing now rather than later.
  6. Mind the metal mark on the finished ring. In Canada, the Competition Bureau requires that platinum carrying a quality mark be "at least 95% platinum", and that a quality mark be accompanied by a trademark applied using the same method.

Price in CAD, and what actually moves it

Both shapes save you money against a round of the same weight, and the princess saves you more. As a rough guide in August 2026, for a well cut natural stone at G colour and VS2 clarity, a one carat round sits around $6,000 to $8,000, a one carat cushion around $4,800 to $6,400, and a one carat princess around $4,200 to $5,800. Those are the shape of the gap, not a quote. Check live stones on our loose diamond search before you plan a budget around them.

One thing that genuinely moves those numbers: loose diamonds trade internationally in US dollars, so every Canadian price sits on top of an exchange rate. The Bank of Canada's daily average rate on 11 August 2026 was 1.3927 Canadian dollars per US dollar. When that figure moves a few cents, retail prices here follow within weeks, in both directions.

With lab-grown stones the shape premium largely disappears. A one carat lab princess and a one carat lab cushion may differ by a couple of hundred dollars. At that gap, ignore price and choose the shape you actually want, then put the saving into a heavier stone or a better setting.

Which one to choose, and what to do next

Choose the princess if you want sharp geometry, the largest visible spread per dollar, a predictable stone you can buy confidently from a video, and you are willing to have the corners properly protected. Choose the cushion if you want a softer, older look, no chipping worry at all, and you are prepared to watch videos closely enough to tell a crushed ice stone from a chunky one.

Start with the setting, since that decides how the corners are held. Browse engagement ring settings, then filter loose diamonds by shape and compare three or four candidates in the 3D preview, where the facet pattern behaves the way it will on a hand. When you have a pair you like, set metal, size and engraving on the complete ring page. Our other guides cover clarity, colour and budget in more depth if you are still deciding.

Sources