Guide to Trillion Cut Diamonds

Trillion cut diamonds have carved out a niche as a fabulous, non-traditional accent stone in jewelry design. But this cut is a lot more versatile than a position as an accent stone gives it credit for. Its unique symmetry and proportions make it a standout choice not just as a side stone, but also to take center stage. Whether you’re looking for a rare standout for your center stone or an unexpected look for accent stones, trillion cut diamonds fit the bill and then some.

History of Trillion Cut Diamonds

The history of the trillion cut diamond is relatively short when compared to other diamond cuts. The triangular shape of the trillion cut was first developed by the Asscher brothers of Amsterdam in the 18th century – the same Asscher family whose namesake is the asscher cut. This shape inspired other triangular diamond cuts, which led to Leon Finker creating the trillion cut in the mid-1960s.

While Finker was unable to trademark the name “trillion” for the cut, the name stuck. Today, all triangular cut diamonds are generally referred to as trillion cuts. They have three sides that are usually of equal length and a flat table on the surface. They are typically faceted differently depending on their usage: 31 facets and straight sides for accent stones and 50 facets and convex sides for larger diamonds to be used as center stones.

When to Go Trillion: Pros & Cons

While all diamond cuts are going to have pros and cons, those of the trillion cut diamond are perhaps more pronounced due to its unusual shape:



  • - They usually look bigger than other diamond cuts of the same carat, like princess cut or round brilliant.
  • - A rare diamond cut, it is a unique choice for a center stone that you won’t see very often.
  • - It exhibits an astonishing amount of fire and brilliance helping to hide inclusions and color.
  • - Its unique shape makes it an instant standout as a center stone on an engagement ring.



  • - The three pointed ends of the trillion cut are vulnerable to chipping and breaking, so it’s important to protect them with prongs or a bezel setting.
  • - Trillion cut diamonds have a shallow cut meaning they’ll need more frequent cleanings as a small amount of dirt or residue will dull the stone.
  • - Since this is a rare cut, you may need extra time and effort to seek out trillion cut diamonds that are high quality.
  • - As shape and proportion can vary stone to stone, it’s best to see the stones in person whenever possible.

Modern Trillion Cut Diamond Ring

Evaluating a Trillion Cut Diamond: The 4Cs  


Like other fancy-shaped diamonds, certification agencies like the GIA do not grade trillion cut diamonds for cut. The structure of this cut is simply too complex and unique to create a universal standard around cut quality. So for cut, your choice should be guided by parameters around some key features and then personal preference.

The generally accepted guidelines around a more ideal cut for a trillion cut diamond break down as the following:

  • - Depth: 32-48%
  • - Table: 50-70%
  • - Length to width ratio: 1.00 - 1.10

The most helpful gradings on the certificate that pertain to cut are the symmetry and polish grades. Choosing a stone with excellent or very good symmetry and polish within the previous stone parameters is a good indicator of a well cut diamond.

For symmetry, the facets on the right and left halves of the stone should have the same shape and size. All the points should meet and there shouldn’t be any missing or extra facets. This layout of facets should perfectly play off of a not-too-shallow depth and mid-sized table in order to reflect a fantastic brilliance and fire throughout the stone.


A trillion cut diamond is able to nicely hide color when it’s a well-cut stone. If it’s not cut well, and especially if the depth is too shallow, more color will show through. Ultimately, how much color a diamond exhibits is a personal preference and can be altered depending on the type of metal you use for the setting.

If you’re set on a white diamond look, you’ll want to choose a cool metal like platinum or white gold and stick to a diamond color grade of H or better. If warmer tones of yellow gold or rose gold are appealing, a color grade of J or better will be accentuated beautifully in those metal settings.


Trillion cut diamonds are fantastic at concealing inclusions and blemishes. Their brilliant faceting style and unique shape allow for really nice clarity conditions. However, since the triangular cut produces three sharp points, it’s best to avoid any larger inclusions in those areas since they will make an already vulnerable part of the stone more fragile.

The best route to take for a trillion cut diamond’s clarity is to look for an eye-clean stone. Whether looking for a center stone or accent stones, an eye-clean stone means that there are no inclusions or blemishes noticeable to the naked eye. But since well-cut trillions are hard to find, you may want to consider every clarity grade from SI2 and up. This way you’ll have options for also getting a good shape and lots of sparkle.


Trillion cut diamonds are usually cut to the ideal proportions and length width ratio for the quality of the stone being cut. So a trillion cut diamond’s carat weight will not necessarily dictate how big or small it looks in person. The stone’s measurements are a better indication of the apparent size.

Finding a variety of trillion cut diamonds in differing carat weights may also be a big endeavor. While they are becoming more popular to see as a center stone, this diamond cut is far more popular being used as an accent stone. So if you’re looking for a center stone, know that trillion cut diamonds of 1 carat or larger and high quality are quite rare.

Choosing an Ideal Trillion Cut Diamond  

Much of the choice when selecting a trillion cut diamond is going to come down to personal preference. For your color grade, first take into consideration the type of setting you want. For the clarity grade, focus on what appears to be eye-clean to you and stay away from larger inclusions near the vulnerable points.

The most coveted trillion cut diamonds have incredible shape appeal. Often shape appeal gets allocated entirely to symmetry. While symmetry is very important to shape appeal, this is not the only marker of an appealing shape. Firstly, trillions should be equilateral triangles so that all three angles are equal and all three sides are the same length.

Secondly, the edges, or sides, of the trillion cut diamond can either be straight or rounded. If they’re straight, they should be entirely flat giving the stone a strong geometric look. Rounded sides have a slightly convex nature to them. The rounded side stones are generally preferred for center stones and the straight side stones are the preference for accent stones. But there’s no rule about this, so go with whatever suits your style.

Lastly, most trillion cut diamonds have sharp, pointed corners, but there are some with cut-off corners. The pointed corner is the most vulnerable part of the stone, being very susceptible to damage. When the corners are cut off, this makes them far less likely to break. However, this will give the diamond a different shape.

Trillion cut diamonds in wedding band

Rough trillion cut diamond ring

Trillion Cut Diamond Prices

It’s a general rule of thumb that fancy-shaped diamonds will always be less expensive at a per carat cost than the most popular round brilliant cut diamond. But although they will typically cost less than the round brilliant cut, the actual cost can vary widely based on the cut quality, clarity, color, and carat weight. And that’s before considering the shape appeal, symmetry, and polish. Also, since most trillion cuts are made to be accent stones in a setting, there will be a certain cost associated with the rarity of a trillion cut diamond that is a larger carat weight.

The popularity of the trillion cut diamond as a center stone is on the rise but it has a long way to go in order to make trillion cuts more prominent as a diamond shape. Currently they stand around twelfth place for the most popular cut and account for only 0.02% of all cut diamonds. This all adds up to being prepared for a higher price tag for larger, high quality stones.

Designing a Ring With a Trillion Cut Diamond

Choose a setting that protects the fragile and vulnerable corners of the trillion cut diamond and you’ll be off to a great start with your design. From there, you can really do no wrong with the diamond cut. It’s incredibly versatile and a lovely complement to many other diamond shapes.

One of the best places to see that is in a wedding band. Two of our favorites are Tempest and Kya where an intricate, curved vintage-inspired design places beautiful trillion cut diamonds alongside round white diamonds for a unique and sparkly look.

When featuring a trillion cut diamond as the center stone, the security of the setting is paramount. For ultra sleek and modern Diana, brilliant marquise cut diamonds flank a stunning trillion cut diamond set in v-prongs for a unique take on a classic three-stone ring.

The chic sophistication of a trillion cut diamond contrasts nicely with nature-inspired looks as you can see with our Maple. A hand-engraved band features a bark-like texture reminiscent of a beautiful Sequoia tree cradling a wondrous pink trillion cut morganite for a spin on a solitaire setting.

Trillion cut diamonds add a strong touch of modernity and adventure to any engagement ring style. Make it more subtle as an accent stone or the center of attention as the main stone and add spectacular sparkle and a unique appeal to any engagement ring.

Trillion cut diamond in engagement ring stack

Side view of trillion cut ring with marquise diamond accents

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