Our No-BS Guide on How To Choose a Diamond Online

1. Select Your Shape

Your (or the person whose diamond you’re shopping for) diamond’s shape is everything, darling. Selecting your diamond shape is the single most important decision you’ll make, and it has almost nothing to do with charts or grades and everything to do with personal style.

After all, the shape sets the entire vibe of the ring. A round brilliant is timeless and fiery, an emerald cut feels architectural and sophisticated, while a pear or oval offers a unique, modern statement.

Why lock this in first? Because the ideal technical specs—the perfect color, clarity, and cut proportions—are completely different for each shape. The strategy for buying a brilliant cushion is not the same as for buying a step cut Asscher. And believe it or not, when it comes to diamond shapes, you’ve got a world of variability:

Round Brilliant Cut Diamonds

The round brilliant is the undisputed classic, and for good reason. Engineered with 58 facets, its sole purpose is to deliver explosive sparkle, fire, and brilliance, making it the most popular diamond shape by a landslide. This timeless cut is incredibly versatile, looking perfect in any setting style, and it’s fantastic at masking slight inclusions or color. The only real con? This popularity comes at a price. Round brilliants are the most expensive shape per carat due to high demand and the significant amount of rough diamond lost during the precise cutting process.

Shop the Look

Emerald Cut Diamonds

An emerald cut doesn’t sparkle; it commands attention. This elegant, rectangular step cut is defined by its long, clean lines and cropped corners, creating a stunning “hall of mirrors” effect. Its major pro is its sophisticated, architectural look that elongates the finger and often appears larger than its carat weight. However, this cut is brutally honest. Its large, open table acts like a window into the stone, meaning it requires a higher color and clarity grade to look its best, as any tint or inclusion is easily visible. It’s the ultimate power-play for those with confident, Art Deco style.

Elongated Cushion Cut Diamonds

The elongated cushion is the perfect diamond for the modern romantic. It takes the soft, pillowy corners of a classic cushion cut and stretches them into a flattering rectangular shape. Its pros are numerous: it offers brilliant, fiery sparkle similar to a round, while its elongated form provides amazing finger coverage and a slimming effect. The main con to watch for is the “bow-tie effect”—a dark shape across the center that can appear in poorly cut stones. A well-cut elongated cushion, however, is a celebrity favorite that combines timeless charm with a chic, modern silhouette.

Shop the Look

Radiant Cut Diamonds

For those who refuse to compromise, the radiant cut is the ultimate hybrid. It brilliantly combines the crisp, rectangular outline of an emerald cut with the fiery, crushed-ice sparkle of a round brilliant. Its biggest pro is its intense scintillation, which also makes it incredibly good at hiding inclusions. The cropped corners offer more durability than a sharp-cornered princess cut, making it a practical choice. The only thing to be mindful of is that a radiant can sometimes show more color than other shapes, so it’s a good idea to ensure you love the hue of the stone you choose.

Marquise Cut Diamonds

Unique, dramatic, and steeped in royal history, the Marquise cut is for those who want to make a statement. Its greatest pro is its impressive size illusion; with the largest surface area of any shape, it looks massive for its carat weight and has a powerful finger-slimming effect. However, its two sharp points are its Achilles’ heel, making them vulnerable to chipping if not protected by V-prongs. A poorly proportioned stone can also display a distracting dark bow-tie. Fun fact: King Louis XV of France reportedly commissioned the shape to resemble the lips of his mistress.

Rose Cut Diamonds

This antique diamond cut, with its flat bottom and domed, faceted top, glows with a subtle, watery luster instead of modern fire. Its main pro is its unique, romantic charm; it was designed to glitter under candlelight, giving it an authentic vintage feel that is impossible to replicate. It also appears large for its carat weight. The con is that it lacks the bright sparkle of a brilliant cut, and its transparency means inclusions can be more visible. It’s a truly artistic choice for the non-traditionalist.

Old Mine Cut Diamonds

Equal parts diamond and a piece of history an old-mine cut is the hand-cut predecessor to the modern cushion. Each natural old mine stone is entirely unique, with a high crown, small table, and a chunky, soulful sparkle. Its biggest pro is its undeniable character; it was cut to look stunning in low light, giving it a warm, romantic fire. The cons are a matter of perspective: they lack the symmetrical precision of modern cuts and are much rarer to find. However, if you’re looking for a more affordable and precise old mine you can always opt for lab grown diamonds, as those will be cut by lasers.

Oval Cut Diamonds

The oval cut is the reigning champion of trendy yet timeless diamonds. Think of it as a round brilliant with a chic, elongated twist. Its biggest pro is that an oval delivers fiery, near-round sparkle while its shape makes your finger look longer and slimmer, and the diamond itself can appear larger than its carat weight. As one of the most popular shapes of 2025, the supply is plentiful. The major con to watch for is the “bow-tie” effect—a dark band across the stone’s center that can appear if the cut isn’t precise. It’s the perfect choice for classic brilliance with a flattering, modern edge.

Cushion Cut Diamonds

A cushion cut is the diamond equivalent of a cozy cashmere sweater—soft, classic, and romantic. This square or rectangular shape with rounded corners was the go-to for over a century before the modern round brilliant. Its pros are its gorgeous, fiery sparkle and its excellent ability to hide inclusions, often making it a great value. The main con is the sheer variety; “cushion” can describe anything from a chunky, vintage-style stone to a modern “crushed ice” look, so you have to see them in person to know what you’re getting. It’s a timeless choice with an undeniably vintage soul.

Asscher Cut Diamonds

Think of the Asscher as the emerald’s captivating, octagonal cousin. A square step cut with deeply cropped corners, its main pro is its mesmerizing Art Deco aesthetic. Instead of sparkling, it produces a “windmill” effect of hypnotic, flashing light. It’s a bold and sophisticated choice for someone with a strong sense of style. The cons? Like an emerald, its clear, open facets demand high color and clarity grades, and its shape can make it appear smaller for its carat weight. As the first-ever patented diamond cut, it’s a true piece of design history.

Shop the Look

Pear Cut Diamonds

A pear cut, or teardrop, is effortlessly elegant and unique. This brilliant cut hybrid of a Round and a Marquise has one major pro: its flattering, elongated shape slims the finger beautifully while offering a standout look. It’s also great at hiding inclusions, especially near its point. However, that single point is also its primary con, as it’s a weak spot that is vulnerable to chipping and requires a protective prong. Symmetry is also non-negotiable for a beautiful pear. It’s a graceful and artistic choice that guarantees you won’t have a ring like everyone else.

Princess Cut Diamonds

The princess cut is for the modern traditionalist who loves sharp lines and major sparkle. As a square brilliant cut, its top pro is its incredible fire and scintillation, which comes close to rivaling that of a round. It’s also one of the best value shapes, as its pyramid-like form preserves much of the original rough diamond. The biggest con is its four-pointed corners, which are fragile and highly susceptible to chipping if they are not fully protected by prongs or better, bezel. Created in the 1980s, it’s a relatively young cut designed for maximum brilliance in a clean, contemporary package.

Old European Cut Diamonds

The old European cut is the romantic, charming ancestor of today’s Round Brilliant. Hand-cut to sparkle in candlelight, its main pro is its unique character; no two are exactly alike. It features a high crown, a small table, and a visible culet, which combine to create a warm, chunky faceting pattern that glows with an inner fire. The con is a matter of taste: it doesn’t have the uniform, splintery sparkle of a modern diamond, and as an antique (when natural), it isn’t graded to today’s strict standards. It’s the perfect choice for a truly authentic vintage ring.

Trillion Cut Diamonds

A trillion cut is a bold, geometric statement. This triangular shape is a brilliant cut, meaning its top pro is its impressive fire and sparkle, which flashes from its three sides. It has a very large surface area, giving it a huge look for its carat weight. Its cons are significant: its three-pointed corners are fragile and require protective settings, and it’s rarely used as a center stone, more often appearing as side stones. For the true modernist, however, a trillion as the main event is an edgy and unforgettable choice.

Misc. Cut Diamonds

If the trillion cut is too traditionalist for you, there’s a world of miscellaneous cuts out there. This category includes artistic shapes like the edgy kite, the romantic heart, and the ultra-minimalist portrait cut. The undeniable pro is their absolute uniqueness; these shapes guarantee a one-of-a-kind ring that is a true piece of wearable art. The cons are primarily practical: supply is limited, and there are no standardized cut grades to follow. However, if you value individuality, you can’t go wrong with an out-of-the-ordinary cut.

2. Decide If You Want a Lab Grown or Natural Diamond

There is no wrong choice here. Both natural and lab grown diamonds are 100% real diamonds—they are chemically, physically, and optically identical. The difference isn’t in the stone itself, but in its origin and your personal priorities.

A natural diamond offers the romance of a finite, billion-year-old gem created by the Earth; you choose it for its traditional story and inherent rarity. A lab grown diamond offers a modern marvel of science; you choose it for its incredible value, which allows you to get a significantly larger or higher-quality stone for the same budget. The right decision is simply what matters more to you: the ancient, rare story or the modern, maximized value.

Why You Shouldn’t Cut Corners on Diamond Cut

A superior cut is what unleashes a diamond’s fire, sparkle, and brilliance. It determines how effectively the stone takes in light and reflects it back to your eye. A poorly cut diamond will look dull and lifeless, regardless of its color or clarity. An expertly cut diamond, however, can look bigger, brighter, and more valuable. It’s the one C that truly breathes life into the stone.

What a Cut Grade Measures

Ok, so from what we’ve mentioned you might assume a diamond’s cut grade is a measurement of its sparkle (aka light return). And that’s true. But only to an extent. There are two other factors that are taken into consideration when assigning cut grades:

• Design: Or, how well the diamond was cut to ensure durability and optimal weight.
• Craftsmanship: Or, the quality of work that went into ensuring your diamond’s facets were polished, symmetrical, and just looking good.

When combined with the Sparkle factor, or, your diamond’s brightness, fire, and scintillation factors, you get a properly graded diamond cut.

Fancy Shape Cut Grades Are Different Than Round Brilliant Cut Grades

This is where diamond buying gets tricky, so pay attention. For round brilliant diamonds, the rules are simple; there’s a scientifically-backed formula for a perfect cut. But for fancy shapes (that’s everything else), there is no single, universally agreed-upon standard for what makes a “perfect” oval or cushion. This subjectivity is why the major gemological labs approach grading them differently.

Because there’s no industry standard, GIA doesn’t offer an overall cut grade on fancy shapes. Instead, they provide grades on polish and symmetry, with an “Excellent” rating in both considered equivalent to the best cut grade available. If you’re still looking for a definitive grade, search for GCAL or IGI-graded diamonds.

Our Recommendation: Go for Good, Very Good, Ideal, Super Ideal & Guaranteed Brilliant

Unless there is another aspect of your diamond that means more to you than sparkle, it’s important to prioritize your cut grade. And in our opinion, any grade below good just won’t cut it. Fair is fine, but the light return, polish, and symmetry just leave too much to be desired. When in doubt, compare diamonds side by side, either in person or online. That way, you can determine if there is a major difference that matters to you between the grades.

Spready Stones = Larger Looking Sparkle

Elongated shapes like ovals, pears, Marquise, and elongated cushions are masters of this illusion. They carry more of their carat weight on their surface, maximizing their length and width. This means they take up more visible real estate on your finger than a round or square diamond of the same weight. If you want the most impressive visual impact for your budget, an elongated shape is one of the savviest choices you can make.

How Big Is Too Big?

Let’s say you’re in the market for an elongated cushion cut lab diamond with a cut grade of “Good” and up, and a budget of $5,000. Within those parameters alone, you’ll come up with over 10k diamonds ranging in sizes from half a carat to over 9! So how do you know what size is right for you? By trying it on, of course. Speak with your fav jeweler, like Frank Darling, about viewing your preferred shape in different sizes. Pay attention to the mm size and carat weight, and note what feels too small, what feels too big, and which is just right.

Our Recommendation: Get Rid of Diamonds That Look Too Small for Their Size

As we mentioned above, depth can, but doesn’t necessarily, affect the brilliance; it affects the size. A deep diamond is always going to look small for the carat weight which means you may be paying for 1 carat, but you’re getting a diamond that looks like .75. Find your shape to the left and key in the depth values for your cut. Your shape isn’t there? We can help. Reach out at hello@frankdarling.com, and we can advise on the ideal diamond depth for your preferred shape.

Ideal Ratios by Shape

If you’re looking for that “spreadier,” more elongated and finger-slimming look, you’ll want a higher ratio. Likewise, if you’re opting for a more antique appearance, you’ll err on the lower side.

• Ovals: Most often found in the 1.3 to 1.5 ratio range. A higher ratio means a more elongated shape. And if you want to take it to the next level you can even opt for a moval shape. Think: If an oval and a Marquise had a baby.
• Emeralds: Like the radiant cut, ideal ratios land somewhere between 1.3 to 1.45 but you can go as high as 1.6.
• Pears: Chunky on the bottom and slim on the top, pears are the ultimate mixed bag. Thanks to the wider bottom, you’ll often see pears with a ratio of 1.4-1.7, with 1.5 creating the ideal pear cut shape.
• Marquise: Looking for a football shaped Marquise? Reach for stones with a ratio of 1.7ish and if you prefer a longer, leaner look you can go as high as 2.15.
• Cushion: A 1 length-to-width ratio will essentially get you a squarish stone. Bump it up to between 1.1 for slight elongation and between 1.2 to 1.3 for a rectangular look. For that super elongated cushion, you can even go as high as 1.4.

The Longer the Length, The Higher the Chance of a Bowtie

The bowtie is the notorious dark shadow that can stretch across the center of brilliant-cut elongated diamonds like ovals, pears, and Marquise. This effect is a cutting flaw, not an inclusion, caused by facets that leak light instead of reflecting it back to your eye. The longer and skinnier the diamond’s proportions, the higher the chance that a distracting bowtie will be present.

Our Recommendation: Listen to Your Heart But Watch Out for Bowties

Here’s the thing: a diamond certificate from GIA or IGI will not mention a bowtie. The only way to avoid a bad one is to visually inspect the stone. When buying online, a high-quality 360° video is non-negotiable. While a faint, subtle bowtie is normal, a dark, prominent one creates a dead zone in the diamond’s sparkle. Your eyes are the final and most important judge.

Specific to Emeralds & Asschers

Eliminate any diamond with less than a VS1 clarity grade. Step cut diamonds show inclusions and investing in clarity is a must.

Specific to Platinum or White Gold Rings

Eliminate any diamond warmer than H. Platinum and white gold show their color. Not sure which one is right for you? Learn about selecting a metal in our guide to metal color.

If You Want a D-F Color Diamond

If you’re planning on picking a diamond in the D-F range, you’ll want to set the fluorescence slider to “none.” Even faint fluorescence can make these diamonds appear blue.

G-H Color Graded Diamond

A good medium ground, if you’re planning on picking a diamond in the G-H range, you’ll want to set the slider to “faint” or “none.”

Choosing an I-M Color Grade

If you’re planning on picking a diamond in the I-M range, you’ll want to set the slider to “medium -> none.” Here, fluorescence can actually make your diamond appear whiter!

Are There Still Too Many Diamonds?

Improve the cut grade to ideal. Still too many? Go ahead and increase your carat weight and color until less than 10 remain.

Are There Too Few Diamonds?

You’ll need to lower your target carat weight or increase your budget.

Are There Not Enough Choices?

If you’re searching for a unique shape like an Asscher, or a large stone, the selection may be limited. If there aren’t enough results, try loosening up your carat weight range until you have more results or contacting us to source something off-menu.