What is a Trillion Diamond?

diamond engagement ring with trillion cut accent stones

A trillion cut diamond, also called a trilliant cut, is a stone that has been cut into a triangular shape. While they’re most commonly used as side stones in engagement rings, the trillion makes for a distinct solitaire if you’re looking for something more unique. In addition to accent stones, the trillion is also a commonly used shape in earrings and pendants. 

What is a Trillion or Trilliant Cut Diamond? 

If you’re researching a triangle shape, you’ll likely encounter them as trilliant, trillion and triangular brilliant diamonds. Leon Finker and Henry Meyer both started creating brilliant cut triangle shapes in the 1960’s- Finker called his trillion while Meyer referred to his as trilliant. The misunderstanding between the similar phrases “trillion” and “trilliant” led each of these words to lose their copyright in the 1980’s. Finker’s business relaunched trillion as “Trielle” and nowadays “trillion” and “triangular brilliant” are used when referring to non-branded shapes. 

Typically trillions are cut in the shape of an equilateral triangle where all three sides have the same length with a flat table or top surface. When used as accent stones, a trillion is usually cut concave or uncurved with 31 facets. When used as a solitaire stone, the trillion is often cut convex or curved with 50 facets which makes the stone appear larger than its carat weight.

Trillion Cut Engagement Rings

Although a more popular choice for accent stones, a trillion can work as a solitaire if you’re looking for an eye-catching alternative to a traditional shape. As long as they aren’t cut too shallow, trillions have incredible brilliance and fire, which can hide inclusions or other flaws in a stone. A trillion has a large surface area which makes it look bigger than other shapes of the same carat size such as round or princess allowing you to get the most out of your stone’s weight. 

Like marquise and heart shaped diamonds, trillions have pointed corners which require extra care to prevent breakage or chipping if set as a solitaire. We recommend setting a trillion in V-shaped prongs or a bezel setting to ensure the diamond is protected. Because trillions have less depth than other cuts they can easily be dimmed by small amounts of dust or dirt, so this diamond shape will require more frequent cleaning than other shapes.

Unlike round shaped diamonds, the Gemological Institute of America doesn’t provide cut grading for trillions due to their complex and unique structure. In addition to cut parameters, you’ll also want to pay attention to symmetry and polish grades and work with a jeweler that you trust. If you have questions about choosing a diamond shape or designing a custom ring give us a call at 303-385-8449 or click here to schedule an appointment.