Diamond Shapes & Buying Tips: Complete Guide to Choosing the Perfect Shape

by Tom Thornbridge

Diamond shape is one of the most visually impactful choices in creating an engagement ring, setting the tone for style and personality. Each shape offers its unique allure, from the classic sparkle of a round brilliant to the sleek elegance of an emerald cut. However, each shape also has specific characteristics and features to consider, ensuring you get the best sparkle and clarity. Here’s a guide to the main diamond shapes, along with expert tips to look out for when choosing each one.

Round Brilliant

The round brilliant is the most popular and classic diamond shape, revered for its exceptional sparkle. Thanks to its precise facet pattern, a well-cut round diamond maximizes light performance, creating a dazzling display of fire and brilliance.

What to Look For:
To ensure your round diamond has optimal sparkle, ask for light performance images, such as ASET or Ideal Scope images. These tools reveal how well the diamond handles light, helping you spot any light leakage and ensure peak brilliance.

A rare 1.04 ct D IF Round Cut Precision Lab Grown Diamond from Whiteflash. Diamonds of this spec are not common, even in lab grown diamonds.

Oval

Oval diamonds have a graceful, elongated shape that gives the appearance of a larger stone compared to round diamonds of the same carat weight. They’re a popular choice for a vintage or unique look, and their shape can also make fingers appear more slender.

Lab-Grown 1.01 Carat F-VS1 Oval Cut Diamond from James Allen

What to Look For:
Ovals can sometimes exhibit a bowtie effect, a dark area across the center of the diamond caused by light leakage. Look for an oval with minimal or well-blended bowtie visibility to maintain sparkle without a distracting shadow. Review images or videos under good lighting to evaluate this feature.

For top-quality lab diamonds and exceptional customer service, start with Whiteflash. Blue Nile and Brilliant Earth are also excellent options to explore for a range of styles and quality in your search.

Princess

The princess cut is a modern, square-shaped diamond that offers a lot of sparkle due to its brilliant-cut facet arrangement. It’s ideal for those wanting a contemporary look with impressive brilliance.

What to Look For
With a princess cut, watch for visible inclusions near the corners, as they can compromise the stone’s durability. Ensure the corners are protected by prongs in the setting to prevent chipping, and aim for a clarity grade that’s eye-clean to enhance sparkle.

1.04 Carat Princess Lab Grown Diamond from Brilliant Earth

Cushion

Cushion-cut diamonds, known for their soft, rounded corners and pillow-like shape, offer a romantic, vintage appeal. This shape combines sparkle with a charming, antique feel, and it’s available in both brilliant and modified brilliant cuts, with the latter offering even more sparkle.

What to Look For
When selecting a cushion-cut diamond, check for depth and symmetry. Avoid overly deep stones, which can make the diamond appear smaller than its carat weight. Light performance images can also help verify that the diamond distributes light evenly for a balanced sparkle.

IGI 1.52 Lab-Grown 1.52 Carat Cushion Modified Diamond from Blue Nile

Radiant

The radiant cut is a hybrid shape, blending the elegance of an emerald cut with the sparkle of a round or princess cut. Its rectangular or square silhouette and brilliant-cut facets create intense fire, making it a stunning choice for those wanting a unique, radiant stone.

What to Look For
Radiant cuts can sometimes exhibit a “crushed ice” effect, where light reflects in small, scattered patterns. For a well-balanced look, choose a radiant cut with evenly distributed brilliance rather than overly concentrated sparkle in certain areas. 

1.54 ct E VVS2 Radiant Cut Precision Lab Grown Diamond from Whiteflash

Emerald

The emerald cut is known for its sophisticated, step-cut facets, creating a mirror-like effect with less sparkle but captivating flashes of light. This elongated, rectangular shape emphasizes clarity and color, making it a popular choice for a clean, elegant aesthetic.

What to Look For
Emerald cuts are prone to windowing—a see-through effect at certain angles due to the larger facets. Look for a diamond with a well-proportioned cut to minimize windowing, and prioritize clarity, as inclusions are more visible in emerald cuts due to their open facets.

IGI 1.00 Lab-Grown 1.00 Carat E-VS1 Emerald Cut Diamond

IGI 1.00 Lab-Grown 1.00 Carat E-VS1 Emerald Cut Diamond from James Allen

Asscher

The Asscher cut is a square-shaped diamond with step-cut facets similar to an emerald cut but with a distinct, almost octagonal appearance. Known for its vintage charm and mesmerizing “hall of mirrors” effect, the Asscher cut is perfect for those who appreciate timeless elegance.

What to Look For
Like the emerald cut, the Asscher’s open facets can make inclusions more noticeable, so prioritize clarity when choosing this shape. Look for a diamond with a well-defined “X” pattern visible through the table, which indicates a well-cut Asscher. Avoid stones with excessive depth, as this can make the diamond appear smaller.

1.05 Carat Asscher Lab Grown Diamond from Brilliant Earth

Pear

Pear-shaped diamonds, also known as teardrop diamonds, combine the round and marquise shapes, creating an elegant, elongated silhouette. The shape helps the diamond appear larger and can add a slimming effect to the finger, making it a popular choice for those seeking a distinctive look.

What to Look For
Pear diamonds can exhibit a bowtie effect, a dark area across the center of the stone. Look for a pear shape with minimal or well-blended bowtie visibility. Also, ensure the point of the pear is protected by a prong in the setting, as this part can be more vulnerable to chipping.

IGI 1.50 Lab-Grown 1.50 Carat Pear Diamond

IGI 1.50 Lab-Grown 1.50 Carat Pear Diamond from Blue Nile

Marquise

The marquise cut is an elongated shape with pointed ends, often chosen for its ability to maximize carat weight, giving the appearance of a larger stone. The marquise’s unique shape also creates a striking, dramatic look, especially in rings with accent stones or a halo.

What to Look For
The marquise shape is also prone to the bowtie effect, so check that it’s subtle or well-distributed. Marquise diamonds can also appear more slender when overly shallow, so aim for balanced depth and symmetry to avoid a “skinny” look. As with the pear, make sure the pointed ends are well-protected in the setting.

1.06 ct E VVS1 Marquise Cut Precision Lab Grown Diamond from Whiteflash

Not all lab diamonds are created equal. Diamonds grown with CVD can sometimes face transparency issues, while HPHT offers greater clarity but at a higher cost. To ensure quality, buy only from companies that rigorously inspect their diamonds. Whiteflash conducts extensive quality checks, while James Allen and Blue Nile also apply strict QC measures on select high-end lab diamonds.

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My primary goal is to offer a free diamond buying help service. With the myriad of choices available in the market, I understand the challenges buyers face.

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