Collection: Round Brilliant Cut Diamonds

A round brilliant is a circular diamond cut with 57 facets, or 58 when the stone retains a culet — a tiny flat facet at the point. The facet pattern is not decorative; it is an optical design, refined from Marcel Tolkowsky's 1919 study of how light behaves inside diamond, and engineered to return as much light as possible back through the top of the stone.

Two reasons, and neither is markup. Cutting a round brilliant discards 40–60% of the original rough crystal — far more than a fancy shape, which is cut to follow the crystal's natural outline. And round is the most in-demand shape in the world, so it carries a demand premium on top. The result is that a round typically costs 25–35% more per carat than a comparable oval, pear or cushion. If visible size matters more to you than shape, a fancy shape will give you more diamond for the same spend.

Round brilliant is the only shape GIA assigns a formal cut grade to, on a five-tier scale from Excellent to Poor. Excellent and Very Good both perform well in the hand. Cut is what actually produces sparkle, so it is the one of the 4Cs we would suggest you compromise on last — a poorly cut D Flawless will look duller than a well-cut G VS2, and cost considerably more.

A stone graded Excellent by GIA in all three finishing categories: cut, polish and symmetry. Cut does the most work of the three. Polish is how smooth the facet surfaces are, symmetry is how precisely the facets align. Triple Excellent is a genuine mark of careful cutting, though it is a grading outcome rather than a guarantee — we would still want you to see the stone.

As a working guide: a table around 54–58% of the diameter, total depth around 59–62.5%, crown angle near 34–35°, pavilion angle near 40.6–41°, and a girdle that is neither extremely thin nor extremely thick. These interact, though — a stone can sit slightly outside those ranges and still perform beautifully, and one can sit inside them and look flat. Numbers narrow the search. They do not finish it.

Rounds hide body colour better than most shapes, because the brilliance breaks light up and disguises tint. G and H usually face up white, particularly set in white gold or platinum. In yellow or rose gold you can often drop further again without seeing a difference, because the metal warms the stone regardless. Colour is graded face-down against a white tray under controlled light — which is nothing like how anyone actually looks at a ring.

Usually not. The facet pattern is very effective at masking inclusions, so plenty of SI1 stones are eye-clean. Where the inclusion sits matters more than the grade — one under the table is far more noticeable than the same inclusion tucked near the girdle, and two stones with identical certificates can look completely different. We check every stone face-up before recommending it.

A well-proportioned one carat round brilliant measures roughly 6.4–6.5mm across. Diameter is what the eye reads as size, not carat weight, so two one-carat stones can look noticeably different depending on how they are cut. A stone carrying extra weight in the pavilion weighs the same and looks smaller.

Solitaire first, because nothing has outlasted it. A single round on a plain band is the reference point every other engagement ring is measured against, and a well-cut stone needs nothing else. Four claws show more of the diamond and give a cleaner, more modern line; six claws hold it more securely and read as slightly more traditional. Both are correct — it is a question of look and, if you are hard on your hands, a little practicality.

Halo frames the stone with a surround of smaller rounds and makes the centre read noticeably larger, which is useful if you are weighing carat against budget.

Three stone suits a round particularly well, with a matched pair either side or tapered baguettes for something more streamlined.

Side stones and pavé put diamonds along the shoulders and lift the whole ring without drawing attention from the centre.

All made to order in our own workshop, built around your stone.

Both are round, but they are different eras of cutting. The old European cut, common from the late 1800s through the Art Deco period, has a smaller table, a steeper crown, a large open culet and chunkier facets — it was cut for candlelight and gives a broader, softer flash. The modern round brilliant is cut for maximum light return and reads much brighter. Neither is better; they are different looks. View our old cut diamonds.

Because our images and videos are taken at high magnification — far closer than any human eye gets to a diamond, and far closer than the standard the stone was graded to.

Clarity grading is done under 10x magnification. That is the international standard: a grader with a 10x loupe decides whether an inclusion is there and how it affects the grade. Online photography routinely runs at twenty, thirty times life size or more, so you are seeing the stone at several times the magnification GIA used to grade it. An inclusion that fills your screen may be something the grader needed a loupe to find at all.

Colour matters too. A white or transparent inclusion — a feather, a cloud, a crystal without body colour — is far harder to see than a dark carbon spot of the same size, because there is little contrast against the diamond around it. Two stones can carry the same grade and look entirely different in the hand for that reason alone.

We photograph at high magnification deliberately. We would rather show you everything than shoot a diamond flatteringly and have you surprised later. But an inclusion that looks obvious on screen is very often invisible in the hand, at arm's length, on a moving finger, in ordinary light.

The grade tells you what is there. The magnification tells you where. Neither tells you whether you would ever notice it — that is a judgement we make face-up, under proper light, on every stone we hold.

Considerably, and it is worth knowing before you compare stones in different places.

Jewellery displays are lit to sell. Rows of halogen or bright LED spots directly above the case flood the stone with intense, concentrated light from every angle. That produces maximum sparkle and, at the same time, washes out inclusions — the scintillation is so busy that small imperfections simply disappear into it. A diamond in a well-lit display case is showing you close to the best it will ever look.

Daylight is the opposite. Soft, diffuse, coming from one direction. Sparkle is quieter, and anything inside the stone has nowhere to hide. Diamond grading uses controlled, colour-balanced daylight-equivalent lighting for exactly that reason — it is neutral, and it is reproducible.

Neither light is dishonest. But if you look at a stone under spotlights and then take it outside, you will see a different diamond, and most of a ring's life is spent in ordinary light.

When you view diamonds with us, you see them under professional diamond grading lights — the same neutral, colour-balanced lighting the laboratories use — and in natural daylight. No spotlit display case. If a stone looks right under those conditions, it will look right anywhere.

Always, and we would insist on it.

A single diamond on its own looks excellent. There is nothing to measure it against, so your eye accepts it. Put a second stone beside it and differences appear immediately that you would never have seen alone — one reads slightly warmer, one has more life, one throws broader flashes while the other glitters more finely.

This is how the trade buys, and it is the only reliable way to judge colour in particular. Colour grading is comparative by definition: graders work against a set of masterstones, not from memory. Your eye works the same way. Two stones a grade apart are obvious side by side and almost impossible to separate one at a time.

So we will put several in front of you. Sometimes that means you choose a lower grade than you came in for because you genuinely prefer how it looks, and sometimes it means you spend a little more because you can finally see the difference. Either way you will know why, which is the point.

No. Every diamond we sell is a natural diamond, and we've never dealt in lab-grown, simulants or treated stones.

A lab-grown stone is a manufactured product. It's grown in a reactor over a few weeks, then mass produced in unlimited quantities in any size or grade. That's the fundamental difference: a natural diamond took billions of years to form and exists in finite supply, while a laboratory-grown one is a commodity with no ceiling on production. It shows in the pricing — as capacity has scaled, lab-grown prices have fallen steeply and continue to fall, and there is no established secondary market for them.

What you're buying with a natural diamond is scarcity and origin. Rare, and natural. It's why we've never sold anything else. Read our full comparison of natural and lab-grown diamonds.

Our diamonds are independently certified, most commonly by GIA, with others graded by DCLA or HRD. The certificate is issued by the laboratory, not by us, and it accompanies the stone when it ships.

Yes. We are in Sydney's CBD and we see clients by appointment, so you can view stones side by side and compare them in person before deciding.

Just ask us. Finding a particular stone is a large part of what we do, and there's no obligation when you enquire. We'll do our best to source the finest quality natural diamond for you.

Our list is smaller than you'll see on some sites, and that's deliberate. Every diamond here is one we've looked at properly before listing it. Many diamond websites show tens or hundreds of thousands of stones drawn from shared trade lists — diamonds held elsewhere that the seller hasn't seen and won't see unless you order one. It looks like more choice, but nobody has assessed the individual stone, and two diamonds with the same details on paper can look quite different.

So if what you want isn't here, tell us what you're after and what you'd like to spend. We'll look for it, check anything we find ourselves, and only show you stones we'd be happy to recommend. If we can't find the right thing at your budget, we'll say so and talk through the options — sometimes a small change in colour, clarity or size makes all the difference.

Either way, you'll only ever be offered a diamond that we have complete confidence in recommending to you, and it will not just be based on the cheapest price.

Yes. Most clients select the diamond first and then the setting — either one of our existing designs or a fully custom piece made to your description or an image. Everything is handmade by our own jewellers.

Yes. We have many loyal customers all over Australia, and we're able to consult by phone and share photos and videos whenever possible.

Distance is not the obstacle people expect. We'll guide you through the options and select the finest quality diamonds and gemstones for you, so you can make an informed decision from wherever you are. The same applies to custom made engagement rings and jewellery — we'll talk you through it and keep you across it as it's made.

We deliver fully insured anywhere in Australia — every capital city, and regional and rural addresses just the same.

If you are able to come in, we'd always rather show you the stones in person — and if you're travelling to Sydney, appointments can be arranged on weekends.

Tell us the number you have in mind and what matters most to you, and we will show you the best stones we hold at that level. We are a diamond merchant, not a retail jeweller — we do not charge retail prices, and we source natural certified diamonds to suit your budget rather than steering you toward whatever is in the display case. Diamond Imports is a foundation member of the Diamond Dealers Club of Australia, and you will deal directly with Daniel throughout.