The Diamond Pro

Trillion Cut Diamond Buying Guide

By Michael Fried
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Bottom Line Recommendation: 

Trillion cut diamonds are uncommon as the center stone in an engagement ring but can look stunning as diamond accents in a three-stone diamond ring.

Because trillion cut diamonds are typically accent diamonds, there’s less of a need to focus on cut, clarity and color than with a center diamond. In general, it’s best to look for diamonds that are eye-clean and appear colorless in relation to their setting.

As always, we recommend buying trillion cut diamond jewelry from a reputable vendor. James Allen and Leibish & Co. both stock a reasonable range of engagement ring settings with trillion cut diamonds, all with excellent images and very competitive pricing.

What is a Trillion Cut Diamond?

1.29ct G/SI1 trillion cut
1.29ct G/SI1 GIA Trillion Cut from Abe Mor for $5,300

A trillion cut diamond, also referred to as a trilliant cut, is a diamond that’s cut into a triangular shape. A typical trillion cut diamond will have three sides of equal length, with a flat table at its surface. 

The trillion cut is a relatively contemporary diamond shape, with its modern history dating back to the 1960s. It’s often viewed as an adventurous and provocative shape, with an eye-catching, contemporary look that certainly stands out from the crowd. 

Unlike most diamond shapes, the trillion cut is more commonly used for side-stone diamonds than for center stones. However, you can also find engagement rings that feature a trillion cut diamond as the center stone. 

Below, we’ve gone into more detail on the shape and appearance of the trillion cut, as well as the history of this diamond shape. We’ve also shared our recommendations for purchasing an engagement ring with trillion cut diamond accents.

Trillion Cut Diamond: The Basics

Hexagonal Trillion Side Stone Diamond Engagement Ring
Hexagonal Trillion Side Stone Diamond Engagement Ring from James Allen

The trillion cut diamond is triangular, with three equal sides. Like the round brilliant cut, a trillion cut diamond has a flat table. The trillion cut is known for having impressive brilliance, great fire and an eye-catching, modern appearance. 

Like other diamonds derived from the brilliant, trillion cut diamonds do a good job of hiding color and inclusions. When cut to a high standard, a trillion cut diamond can look absolutely stunning, either as a center stone or as an accent diamond. 

Trillion cut diamonds can differ in cut and shape depending on whether they’re intended for use as center or accent stones.

When a trillion cut diamond is intended to be used as a center diamond in a solitaire ring, it will typically be cut to have 50 facets. Center trillion diamonds will also usually have a light curve or convex shape to maximize the diamond’s perceived size.

When a trillion cut diamond is intended to be used as an accent diamond — for example, as a side accent in a three-stone engagement ring — it will typically be cut with 31 facets and won’t have convex edges. 

Thanks to its long sides, a trillion cut diamond can often appear to be larger than its true carat weight. 

The trillion cut, as we know it today, was trademarked by the Henry Meyer Diamond Company of New York in the 1960s as the “trilliant” cut. However, early trillion cut diamonds are believed to have been cut in Amsterdam as long ago as the 19th century. 

trillion cut

The trilliant name comes from the diamond’s shape — a combination of the words “triangle” and “brilliant.” 

Over the years, numerous variations of the trillion cut have been produced, often with different shapes and facet counts. Because of the variation in cut between different trillion cut diamonds, it’s important to pay close attention to photos when you’re comparing diamonds in this cut.

Trillion Cut Diamonds: Price

Like other diamond shapes, trillion cut diamonds can vary hugely in price based on their color, clarity, cut quality and carat weight. Diamond prices increase exponentially with size, meaning you’ll pay significantly more per carat if you’re looking for a particularly large diamond.

Since most trillion cut diamonds are part of a setting, the price can vary based on the type of setting, the number of diamonds and the total carat weight. 

Are Trillion Cut Diamonds Rare?

Trillion cut diamonds are quite rare, especially as center stones. Few jewelry stores keep trillion cut diamonds in stock, with the notable exception of trillion cut diamonds used as accent stones in three-stone engagement rings.

Tips for Buying a Beautiful Trillion Cut Diamond

If you’re buying an engagement ring that features trillion cut diamond accents, there’s not much of a need to obsess over the four Cs. Instead, focus on matching the center diamond to the side diamonds by choosing a center stone with similar clarity and color grades. 

A three-stone ring with trillion diamond accents is usually the best choice. This offers the modern appearance of a trillion cut with a larger selection of center diamonds for you to choose from.

Yellow Cushion 3 Stone Trillion Diamond Ring
Yellow Cushion 3 Stone Trillion Diamond Ring from Leibish

If you’re buying a loose trillion cut diamond, or if you specifically want a trillion cut diamond as a center stone, we recommend using the following tips:

  • Check the diamond’s depth. Trillion cut diamonds are often cut quite shallow. This is helpful for creating the illusion of a larger diamond, as more of the diamond’s weight is distributed horizontally rather than vertically.

    An overly shallow could may affect a trillion cut diamond’s brilliance and fire, giving it a less impressive appearance despite the illusion of larger size. Because of this, it’s best to avoid stones that are cut very shallow — instead, look for moderate depth.
  • Choose an eye-clean diamond. There’s no need to overpay for a diamond that has a flawless clarity grade, especially for a shape like the trillion cut that conceals inclusions and blemishes well.

    Because trillion cut diamonds are mostly used for settings, a very high clarity grade isn’t particularly important. Instead, we recommend focusing on diamonds that are eye-clean, meaning they don’t have any inclusions or blemishes that are visible to the naked eye.
  • Choose a diamond that looks colorless in relation to its setting. Just like with clarity, there’s no need to pay more than you need to for a diamond with a “colorless” D, E or F color grade. Instead, it’s better to choose a diamond that looks colorless in its setting.

Where to Buy Trillion Cut Diamond Jewelry

Jewelry featuring trillion cut center diamonds isn’t particularly common. As such, most diamond vendors don’t stock loose trillion cut diamonds. However, engagement rings featuring trillion cut diamond accents are quite common. 

If you’re looking for a side-stone engagement ring that features trillion cut diamond accents, we recommend buying from a trusted online vendor such as James Allen or Leibish & Co.

James Allen and Leibish stock a small selection of three-stone engagement rings that feature trillion cut side diamonds. For example, this three-stone setting, this double halo setting or this hexagonal setting both use trillion cut diamond accents. 

If you’d like to buy loose trillion cut diamonds, or an engagement ring featuring a center stone in the trillion cut, it’s best to contact Abe Mor. They can help you view a range of trillion cut diamonds in your price range.

About the author
Michael Fried
Mike learned the diamond business from the ground-up at Leo Schachter Diamonds - one of the world's top diamond manufacturers. He has been recognized as a diamond industry expert by Time, PeopleMoney, The Daily Mirror, NerdWallet, The Times Herald, Yahoo Finance Australia, The Art of Charm, The Washington Diplomat, The Next Web, and more.
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