Cushion Cut Diamond
A cushion cut is a square or slightly rectangular diamond with softly rounded corners, like a pillow. It has a vintage look, throws plenty of fire, and usually costs less per carat than a round brilliant.
Key Takeaways
- A cushion cut is a square or slightly rectangular diamond with rounded, pillow-like corners. It descends from the old mine cut, which was one of the most common diamond cuts from the early 1700s to the late 1800s, and that history is where its vintage feel comes from (GIA).
- Cushions come in two main looks: "chunky" (big, bold flashes) and "crushed ice" (fine, glittery sparkle). The style changes both the sparkle and how easily you'll see inclusions.
- For a square cushion, a length-to-width ratio near 1.00โ1.05 reads square; 1.10โ1.20 gives a soft rectangle.
- GIA does not give cushion cuts an overall cut grade โ only round brilliants get one โ so you judge the sparkle by eye (GIA).
- A cushion usually costs less per carat than a round of the same colour and clarity, which is a big reason couples pick it.
What is a cushion cut diamond?
A cushion cut is a square or slightly rectangular diamond with softly rounded corners and curved sides โ the shape of a pillow or a cushion, which is exactly where the name comes from. It's a brilliant-style cut, meaning the facets are arranged in a starburst pattern to bounce light back at your eye, so it sparkles with real fire rather than the long, calm flashes you get from a step cut like the emerald cut diamond.
The cushion is the modern descendant of the old mine cut, one of the most common diamond shapes from the early 1700s through the late 1800s, before electric light and modern saws made the round brilliant possible (GIA). That heritage is why a cushion looks warm and a little antique next to a crisp, contemporary shape. On our Coquitlam bench it's one of the cuts people reach for when they want something with character rather than something that looks like every other ring.
Chunky vs crushed ice: the two cushion looks
Here's the thing most buyers don't realise until they see two cushions side by side: not all cushions sparkle the same way. The facet arrangement splits them into two camps, and the difference is obvious once you know to look for it.
- Chunky (classic / antique-style): Fewer, larger facets. The stone flashes in big, distinct blocks of light. It looks more vintage and more like a true old-style cushion. The trade-off is that those open facets don't hide flaws, so a chunky cushion really wants a cleaner clarity grade or you'll see inclusions under the table.
- Crushed ice: An extra row of facets breaks the light into hundreds of tiny sparkles, like sunlight on shattered ice. GIA calls a cushion with extra crown or pavilion facets a "modified cushion brilliant" (GIA). The glittery scatter hides small inclusions well, so you can usually drop a clarity grade and still get an eye-clean stone for less money.
Neither is "better." Chunky suits people who love a bold, retro flash; crushed ice suits people who love fine, restless sparkle and want to stretch the budget. The only mistake is buying online without knowing which one you're getting, because the certificate won't spell it out for you.
The best length-to-width ratio
The length-to-width ratio tells you how square or rectangular the stone looks. You get it by dividing the length by the width from the diamond's measurements. A ratio of 1.00โ1.05 reads as a true square and suits a classic cushion or a halo setting. Push to 1.10โ1.20 and you get a soft rectangle โ a slightly elongated, flattering look. Go 1.20 and up and the stone reads as clearly elongated, which makes it look larger for its weight and lengthens the finger.
There's no single right number. If you want the stone to look square, stay near 1.00โ1.05. If you like the elongated effect โ the same reason many people choose the oval cut diamond โ push toward 1.10โ1.20 or beyond. Beyond the ratio, look at the corners and sides in person; some cushions are nearly square with gentle corners, others are rounder and more "cushiony," and that's purely down to taste.
Cushion vs round vs princess
These three get cross-shopped constantly, so here's the honest comparison.
| Feature | Cushion | Round brilliant | Princess |
|---|---|---|---|
| Shape | Pillow, rounded corners | Circle | Square, sharp corners |
| Sparkle style | Fire, vintage glow | Brightest, most brilliant | Crisp, modern, mirror-like |
| GIA cut grade | No overall grade | Yes | No overall grade |
| Corner durability | Strong (rounded) | No corners to chip | Vulnerable (sharp points) |
| Price per carat | Lower than round | Highest | Lower than round |
The round brilliant cut diamond is the sparkle benchmark, and it's the only shape GIA gives an overall cut grade to, because rounds are standardised enough to score โ fancy shapes like cushion and princess are still graded for polish and symmetry, just not given an overall cut grade (GIA). You pay for that consistency and demand. A cushion trades a little of that pure brightness for warmth, vintage character, and usually a friendlier price. Against a princess, both can look square, but the cushion's rounded corners are far less likely to chip than the princess's sharp 90-degree points, which almost always need protective prongs.
Buying a cushion: what to watch
Because there's no cut grade to lean on, you're the judge. Three things matter most. First, decide chunky or crushed ice before you shop, since it changes everything about how the stone reads. Second, match clarity to that choice โ go cleaner for chunky, relax a little for crushed ice. Third, look at the stone face-up in real light, not just on paper โ GIA's own advice for fancy shapes is to view them in daylight and compare stones of the same shape and cutting style (GIA). A certificate confirms colour, clarity, and measurements, but it won't tell you whether the diamond actually sparkles to your eye.
This is where seeing stones in person earns its keep. We keep cushions on hand at our Coquitlam studio and can show you a chunky and a crushed ice next to each other so the difference clicks. If you're building a ring around one, our custom engagement ring guide walks through settings, and the full diamond shapes guide compares every cut if you're still weighing your options.
Frequently Asked Questions
Is a cushion cut diamond cheaper than a round?
Usually, yes. Cushion cuts typically cost less per carat than round brilliants because cutting a round wastes more of the rough crystal and rounds are in higher demand. A cushion of the same carat, colour, and clarity often comes in noticeably lower, which is a big part of its appeal.
What is the difference between chunky and crushed ice cushion cuts?
It's the facet pattern. A chunky cushion has fewer, larger facets that flash in big, bold sections. A crushed ice cushion has more, smaller facets that scatter light into a glittery, broken-ice look. Chunky shows inclusions more easily, so it suits higher clarity; crushed ice hides small inclusions, so you can often go a clarity grade lower and stay eye clean.
What is the best length-to-width ratio for a cushion cut?
For a square-looking cushion, aim for about 1.00 to 1.05. For a soft rectangle, 1.10 to 1.20 is the popular range. There's no single correct answer โ it depends on whether you want the stone to read square or gently elongated.
Does GIA give cushion cuts a cut grade?
No. GIA only issues an overall cut grade for round brilliant diamonds. Cushion and other fancy shapes are still graded for polish and symmetry, but not given a single cut grade, so you judge the sparkle yourself or have a jeweller help. We do that in person at our Coquitlam bench.
Is a cushion cut good for an engagement ring?
Yes โ it's one of the most popular fancy shapes for engagement rings. It has a romantic vintage feel, plenty of fire, pairs beautifully with halos and pavรฉ, and generally costs less than a round of the same size. The rounded corners are also less prone to chipping than sharp-cornered shapes.
How does a cushion cut compare to a princess cut?
Both can look square, but a princess has sharp, pointed corners and a crisp, modern sparkle, while a cushion has soft rounded corners and a warmer, vintage glow. The princess's sharp corners are more vulnerable to chipping and usually need protective prongs; the cushion's rounded corners are more forgiving.