Next day shipping on selected items!

Trillion cut diamond guide

on June 08, 2023

When it comes to unique diamond shapes, modified triangular cuts, known commercially as Trillion cuts are without a doubt one of the most eye-catching.

While this cut is not exactly popular when it comes to center diamonds, its visually striking appearance and geometric pattern gives it a powerful quality to accentuate the overall aesthetic of the jewelry.

This is certainly a cut that should not be overlooked.


Historical Context: Trillion cut diamond

Triangular cut diamonds became popular thanks to the design of Leon Finker who developed this triangular diamond shape called "Trillion" in the early 1960s. Almost at the same time, but at the end of the decade, Henry Meyer Diamond Company developed a very similar cut, which they registered under the trademark "Trilliant".

To protect their respective creations, both brand owners patented their designs, although the general public rarely appreciated the subtle differences between the two.

In 1986 a judge ruled that the terms "Trillion" and "Trilliant" were equivalent, and although Finker's design came to market first, Henry and Meyer's patent was filed several years earlier, so Trillion lost its trademark.

Thus, Finker relinquished the name to the public and his new patent was renamed Trielle. Since then, hundreds of variants of the triangular cut have emerged and almost all are known as Trillion.


General Characteristics: Trillion cut diamond

The Trillion cut is especially good for those who are looking for central diamonds with high brilliance, but with an absolutely unique appearance. Being one of the rarest diamond cuts today, it manages to surprise and captivate easily.

We are talking about a triangular shaped cut that has between 31 and 50 facets depending on the target with which the stone will be set. They are usually implemented in rings in two ways:

  • As a striking and shiny center stone, being cut with 50 facets with curved edges.
  • Complementary side stones in three-stone rings. They are cut with 31 facets leaving pointed edges.

This particular cut optimizes carat weight very well, almost better than any other.

There are so many variations of the triangular cut on the market that it is difficult to establish exact parameters of a "perfect" cut. This makes the beauty of the cut very subjective.


Cut proportions

Although it is difficult to establish an "ideal" pattern of a cut with such a wide variety of variations, it is not impossible to have reference measurements.

In this type of cut the weight is better distributed at the top, so it is normal for the Trillion to be shallow.

As it is commonly selected as a complementary side stone in three-stone designs, it is more likely that color and cut will not be your primary concern.


Color and Clarity

In terms of clarity, aim for values that are at the very least SI, clean to the eye. Being a brilliant cut its internal properties are very naturally disguised. Color expectations range between H+ for white gold or platinum pieces and can easily drop down to a J+ range if the setting is a bright yellow or rose gold.



We understand that the Trillion is a shallow cut, but set a limit between 35 and 46% of the diamond's width as a percentage of depth. Going outside of these values can easily result in light leakage or unattractive patterns.



The table (the flat top), should range between 56 and 66% of the total width of the diamond. If the table is too large it will be difficult for the top facets to disperse the light as required. If it is too small, your diamond will not shine brightly enough.


Length x Width Ratio

When it comes to length and width proportions, it all depends on whether the cut is intended for a center setting or will be shown off on the sides. The most attractive proportions range from 1.00 (equal width and length) to 0.95-1.05.


Trillion Cut Symmetry Judgement

How would you judge an ideal Trillion cut? Basically symmetry is what defines the overall aesthetics of this cut which is, by definition, a diamond made up of three exactly equal sides. Make sure the points are the same size or at least look the same.

Another aspect that should not be overlooked is the type of tips, as they can be pointed or rounded. This will completely change the aesthetics of the stone. Generally, rounded edges are more subtle and romantic while sharp ones are more striking.

Finally decide on the edges of the diamond. These can be curved or flat. Curved edges look larger and are especially preferable for center settings. Flat edges give much more character to the cut, geometrically speaking, so they are ideal as a side stone.


Trillion cut diamond settings

Perhaps one of its most striking characteristics is that when set in a three-stone setting, the stones are accentuated and the whole piece stands out strongly.   Together with a cushion cut, it can be one of the most impressive combinations in this type of engagement ring.

Albert Hern's stunning Platinum 2 Trillions & Cushion Ring is a good example.

As you may notice the Trillion side diamonds have a visual effect that seems to elongate the center diamond, looking like a single large rock.


Pros and Cons of a Trillion Cut Diamond

Like any cut on the market, this shape has its advantages and disadvantages that can help you decide if it is your ideal alternative:


The main advantages of the Trillion cut are:

  • Great brilliance and fire as they are inspired by a round cut.
  • They have a unique appearance in today's market.
  • They look bigger than any round or princess cut.
  • They do not require large investments in clarity or color.
  • They are more economical than a round cut (of equal characteristics).
  • Great style and desirable aesthetics.


Potential disadvantages of the cut are:

  • Brittleness of the tips (minimized by covering them with crimp).
  • They get dirty easily which diminishes their brilliance.
  • They are difficult to get in good cutting proportions.
  • Their position cannot be varied too much.

Please note, comments must be approved before they are published


Net Orders Checkout

Item Price Qty Total
Subtotal $0.00

Shipping Address

Shipping Methods