Princess Cut Lab Grown Diamond: The Complete Buying Guide

A beautiful princess cut lab grown diamond is a square (or near-square) diamond with sharp corners, strong sparkle, and a length-to-width ratio between 1.00 and 1.05 for a true square look. It is the same carbon crystal as a mined diamond, IGI or GIA certified, and typically costs 40-70% less than the mined equivalent. The two things that separate a great princess from an average one are corner protection (the points are fragile and need prongs over them) and depth, because a deep princess hides weight you paid for instead of showing it across the top.

This guide covers what defines a strong princess, the ratio and proportions to look for, the settings that protect it, and how it prices against other shapes so you can buy with your eyes open.

What makes a princess cut beautiful

The princess (technically a square modified brilliant) is the most popular fancy shape after the round. It packs a lot of sparkle into a square outline, which gives it a sharp, modern look that a round cannot. When a princess is cut well, light returns evenly across the whole face and the four corners stay crisp instead of looking chipped or soft.

What you are really judging is brilliance and contrast. A good princess shows a bright cross or X pattern from the pavilion when you look straight down. A poorly cut one looks dark in the center, glassy, or "windowed," where you can see straight through it. Because princess cuts are not graded for cut as strictly as rounds on most certificates, you have to use your eyes and the measurements, not just the grade.

If you want a primer on how cut, color, clarity, and carat work together before you shop, our 4Cs guide breaks each one down in plain language.

The ideal length-to-width ratio

Length-to-width ratio tells you how square or rectangular the stone looks from above. For a princess:

• 1.00 to 1.05 reads as a true square. This is what most people picture when they say "princess cut."
• 1.05 to 1.10 looks square to the naked eye but gives you a touch more length, which can flatter shorter fingers.
• Above 1.10 starts to look like a rectangle. That can be a deliberate, elongated style, but it is no longer the classic square princess.

There is no single "correct" ratio, only the one you prefer. The mistake to avoid is buying a stone that is slightly off-square by accident (say 1.07) when you actually wanted a perfect square. Always check the measurements on the certificate, not just the photo.

What to watch for: corners, depth, and spread

Protect the pointed corners

This is the single most important thing about a princess. Those four sharp corners are the most vulnerable point on any diamond shape. A knock against a doorframe or countertop can chip an unprotected corner. A lab grown princess is exactly as hard as a mined one (10 on the Mohs scale), but hardness is not toughness, and points concentrate stress.

The fix is simple: choose a setting with prongs that cover all four corners. V-prongs (also called chevron prongs) wrap each corner and are the standard, smart choice. Avoid any setting that leaves a corner exposed for the sake of looks.

Watch the depth

Princess cuts are often cut deep to save rough weight. A deep stone carries its carat weight downward into the pavilion instead of spreading it across the top, so a deep 1.00 ct can look smaller face-up than a well-proportioned 0.90 ct. Look for a total depth percentage in roughly the 65-75% range and compare the face-up millimeter measurements between stones of the same carat. Bigger numbers across the top mean more visible size for your money.

Mind the spread

Spread is how large the diamond looks from above relative to its weight. Because the princess wastes very little rough during cutting (around 80% of the crystal is retained, versus closer to 40% for a round), you often get more face-up size per carat than a round of the same weight. That is part of why princess cuts feel like good value.

You can filter by exact measurements, depth, and ratio in our diamond search tool so you are comparing real proportions instead of marketing photos.

The settings that suit a princess

The right setting does two jobs: it protects the corners and it complements the square outline. A few that work well:

• Solitaire with V-prongs. The cleanest way to show off a square diamond. Four prongs, each shaped to cup a corner. Timeless and the safest for daily wear.
• Halo. A frame of small diamonds around the center makes the princess look larger and, helpfully, surrounds and shields the corners. Square or cushion halos echo the shape best.
• Channel-set or bezel accents. Channel-set side stones sit flush and snag-free, which suits an active lifestyle. A full or partial bezel offers the most corner protection of any style, at the cost of a little sparkle from the sides.
• Three-stone. A princess center flanked by tapered baguettes or smaller princesses reads architectural and clean.

If you want to see how these look on real rings, browse our princess cut lab grown engagement rings and start narrowing down the metal and setting style you like.

How a princess prices versus other shapes

Among the common shapes, the princess is one of the better values, and lab grown widens that gap further.

• Versus round. A round brilliant of the same carat and quality usually costs more, both because rounds command a premium and because cutting a round wastes more rough. Expect a princess to run meaningfully less than a comparable round.
• Versus emerald or asscher. Pricing is broadly in the same neighborhood, with step cuts sometimes a touch cheaper because they hide inclusions less well and demand is lower.
• Versus oval, pear, marquise. These elongated fancies are often priced close to the princess; the choice is about look, not budget.

Across the board, choosing lab grown over mined saves roughly 40-70% for the same size and quality. We do want to be straight with you on one point: lab grown diamonds currently have lower resale value than mined diamonds. If you are buying as a financial asset, that matters. If you are buying a ring to wear and keep, it usually does not, and the savings go toward a larger or cleaner stone instead.

For the full background on how these stones are made and certified, see our overview of princess cut lab grown diamonds.

Frequently asked questions

Are lab grown princess cut diamonds real diamonds?

Yes. A lab grown diamond is pure crystallized carbon with the same chemical, physical, and optical properties as a mined one. It is graded by the same labs (IGI and GIA), sparkles identically, and tests as a diamond. The only difference is that it was grown in a few weeks rather than over geological time.

Do princess cut corners really chip that easily?

They will not chip from normal wear once they are set properly. The risk comes from leaving the corners exposed or taking a hard, direct hit. Choose a setting with V-prongs or a bezel that covers all four corners and the stone will hold up to daily life. Hardness is the same as any diamond; the corners just need backup.

How big does a princess look compared to a round of the same carat?

Because the princess retains more of its rough and has a wider face-up footprint per carat, it often looks similar in size or slightly larger from above than a round of the same weight, depending on how deep each stone is cut. Compare the face-up millimeter measurements rather than carat alone.

Ready to choose your stone

A great princess comes down to a near-square ratio, sensible depth, and a setting with V-prongs that guards the corners. Diyona is online only, our lab grown diamonds are IGI or GIA certified and made to order, and every ring is backed by a lifetime warranty on manufacturing defects with 30-day returns. When you are ready, browse our engagement ring collection to pair your princess with a setting built to protect it.