Find Your Perfect Diamond
Made to sit flush against the engagement ring it was designed for.
Every ring is made from start to finish in our Los Angeles atelier.
Fifty seven facets arranged to return the most light a diamond can return. The round brilliant is the most studied, most standardized, and most demanded shape in the world, and the one where the certificate tells you nearly everything.
The modern round brilliant is a mathematical object as much as a gemstone. Its 57 facets, 58 with a culet, follow proportions first calculated by Marcel Tolkowsky in 1919 and refined by a century of optical research since. The crown gathers light, the pavilion returns it, and when the angles are right, nearly every ray that enters the stone comes back to your eye as brightness, fire, or scintillation.
No other shape has this much science behind it. Round is the only shape to which GIA assigns a formal cut grade, which means it is the only shape where a single word on the certificate, Excellent, carries a laboratory judgment of how well the stone performs. That standardization is the round brilliant’s quiet advantage: you can compare two rounds on paper with a confidence no fancy shape allows.
The price of all that light is rough. A round brilliant surrenders more of the original crystal in cutting than any other shape, and demand for rounds is the deepest in the market. Both realities show up in what you pay per carat relative to fancy shapes.
| Facets | 57 to 58 |
| Cut grading | Formal GIA cut grade, the only shape with one |
| Light return | Highest of any shape |
| Face-up size | Compact for its weight |
| Relative price | Highest per carat of all shapes |
| Best for | Maximum brilliance, timeless proportions |
A round brilliant hides some of its weight below the girdle, so it faces up slightly smaller than elongated shapes of the same carat. What it gives up in spread it repays in light: a well cut round reads brighter than any other shape at the same size, and its brilliance masks color and small inclusions better than most.
| Carat Weight | Typical Diameter | How It Wears |
|---|---|---|
| 0.50 ct | 5.0 to 5.2 mm | Delicate, precise, ideal in pavé or halo company |
| 0.75 ct | 5.8 to 6.0 mm | A confident everyday presence |
| 1.00 ct | 6.4 to 6.5 mm | The classic benchmark, balanced on nearly every hand |
| 1.50 ct | 7.3 to 7.5 mm | Noticeable spread with serious light return |
| 2.00 ct | 8.0 to 8.2 mm | A statement stone that still wears cleanly |
| 3.00 ct | 9.2 to 9.4 mm | Commanding, best carried by a substantial setting |
Measurements are typical for well proportioned stones. Individual diamonds vary with their cutting.
Because the laboratory grades cut on rounds, the certificate does more of the work for you here than on any other shape. Read it in this order.
Cut grade drives everything a round does. Insist on GIA Excellent or IGI Ideal, with Excellent polish and symmetry. A round with a lesser cut grade is giving away the one thing the shape exists to deliver.
Within Excellent, the best performers cluster around a table of 54 to 58 percent and total depth of 59 to 62.6 percent. Stones cut for beauty sit here. Stones cut to save weight drift outside it while keeping the grade.
A round's brilliance forgives. Many buyers step down to G or H color and VS2 or SI1 clarity, confirm the stone is eye clean, and put the difference into cut quality or carat weight. This is the shape where that trade works best.
Every stone we recommend is scored by ROSI™, our gemological intelligence, built by our gemologists, and verified by a human eye before it reaches you. Request a ROSI™ Score Report on any diamond you are considering, ours or anyone else’s.
Found a round brilliant you are considering, here or anywhere else? Send the GIA or IGI certificate number and our gemological team returns its ROSI™ Score and a read of where it sits in the current market. Complimentary, within minutes.
Score a DiamondWhere stones of the same exact specifications are trading on the open market right now. You get a straight answer, even when the diamond is not ours.
The round brilliant is the most versatile center stone there is. These three directions cover most of what our clients choose, and every setting in our atelier is made to order around your exact stone.
Six prongs of nothing but metal and light. The solitaire exists because a well cut round needs no help, and it remains the setting most rounds go home in.
A circle of pavé diamonds that visually extends the center stone and multiplies sparkle. The classic route to more presence without more carat weight.
Pavé beneath the basket, a peekaboo halo, engraving inside the band. Quiet craftsmanship that reveals itself only to the wearer, and to anyone who looks closely.
If you want the most light and the easiest decision, buy a round. If you want the most size for your money, look elsewhere.
The round brilliant carries the highest price per carat of any shape, and it faces up smaller than ovals, pears, and marquise stones of the same weight. Those are real trade-offs and we will not pretend otherwise. What you get in return is the best documented, best performing, most liquid diamond shape in existence, and a stone that will never look dated. If maximizing finger coverage matters more to you than maximum brilliance, an oval or pear deserves your attention, and we will tell you so.
We are a Los Angeles fine jewelry atelier with family roots in the diamond trade going back to 1967. That history buys you four things you will not find together anywhere else.
Send us the certificate of a stone we do not sell and we will still score it. No other jeweler will grade a competitor’s diamond for you and tell you if it is the better buy.
Every ROSI™ report shows where stones of identical specifications are trading right now, drawn from live market data. You see the range before you see our price.
Every score is verified by our gemological team before it reaches you, and John Anderson, our Lead Gemologist, is one phone call away for the questions a report cannot answer.
Every setting leaves our Los Angeles atelier built around your exact diamond, at one confident price, with 40 day returns and 60 day complimentary resizing behind it.
Our gemologists buy inside a written window, and decline outside it. These are those numbers, published in full, so you can hold any round brilliant to the same standard we do, including one you are considering somewhere else.
The round is the only shape a laboratory assigns a cut grade to, so its window is the tightest we publish and it carries two constraints no other shape does: a crown angle ceiling and a fluorescence limit.
Each scale shows the measurement range. Gold marks the RockHer Ideal window.
| Depth | 59.5% to 62.5% |
|---|---|
| Table | 54% to 59% |
| Girdle | Thin to slightly thick |
| Polish | Very Good or better |
| Symmetry | Very Good or better |
| Culet | None |
| Cut grade | Very Good to Excellent |
| Crown angle | No steeper than 36 degrees |
| Fluorescence | None to Faint |
Every diamond in our search carries these measurements on its report. In the filter panel, under RockHer’s Best, switch on Ideal Cut and the results narrow to the window above. Super Ideal Cut narrows them further still, to a tighter standard our gemologists hold diamond by diamond rather than publish as a range.
Nothing is hidden behind the switch. It applies the same numbers printed on this page.
Open the Round Brilliant diamond searchThe panel as it appears in the diamond search, with Ideal Cut switched on.
Proportion is the first filter, not the last. A round brilliant can sit inside every range above and still be one we will not sell. These findings end a purchase in our office whatever the certificate says, and every diamond scored by ROSI™ is read against them by a gemologist before it is offered.
A certificate tells you what was measured. It does not tell you what was rejected.
Two round brilliant diamonds can carry the same carat, color, clarity, and grading laboratory, and one of them will never reach a client of ours. That gap is the work: reading the plot, the finish, and the face-up appearance against a written standard rather than against a price.
John Anderson, our Lead Gemologist, reviews round brilliants with clients every day. Send him the certificate of any stone you are considering and he will tell you what the paper says and what it leaves out. The consultation is complimentary and there is no obligation.
1-800-779-1726