A diamond's cut affects its brilliance more than its carat, because it's the proportions and angles of the cut that determine whether light reflects towards the viewer's eye or escapes sideways and is lost in the stone. A well-cut 0.50 ct diamond can shine brighter than a poorly cut 0.70 ct stone, even though it is smaller and less expensive. This is one of the few situations in jewelry where less is more.

What exactly does cut do?

Cut refers to the arrangement and angles of a diamond's facets relative to each other, graded by the GIA into five classes: Excellent, Very Good, Good, Fair, and Poor. With an Excellent cut, light entering through the top of the stone reflects internally and returns to the eye almost entirely, as if the stone itself generates its own internal light. With a Poor cut, a significant portion of the light escapes through the sides or bottom, making the stone appear dull, even if it has high clarity and color. This difference means that two diamonds with identical parameters on paper can look completely different on the finger in natural daylight.

Why carat attracts attention first

Carat is easy to compare: 0.70 ct is more than 0.50 ct, so it's naturally associated with a better choice. However, the same stone with a poor cut can look less impressive than a smaller diamond that sparkles with every movement of the hand, because the eye reacts to brilliance, not to the stone's weight in carats. It's a bit like a voice: it's not about how much someone has to say, but how brightly what they say illuminates the room, and a diamond works on exactly the same principle.

How to benefit financially from this

The price of a diamond increases non-linearly with carat: in the Promise collection, a ring with a 0.50 ct round diamond starts at PLN 24,500, while a 0.70 ct one starts at PLN 38,500, which is 57 percent more for 40 percent more weight. By choosing a smaller stone with an Excellent cut instead of a larger one with a Very Good cut, you can spend significantly less and get a ring that optically looks just as impressive. The saved difference can then be allocated, for instance, to a wedding or a first shared apartment, instead of on carats that no one will see with the naked eye anyway.

How to check the cut before purchasing

The GIA certificate directly states the cut grade, but it's also worth seeing the stone in person: a well-cut diamond sparkles evenly from every angle, and with a slight movement, clear, sharp flashes of light are visible instead of a hazy, milky glow. At BELLER, every diamond above 0.3 ct has a Very Good cut or higher, and in the atelier, you can compare several stones side by side in the same light to see the difference with your own eyes, rather than relying solely on numbers on paper.

Frequently asked questions about diamond cut

Is cut the same as diamond shape?

No. Shape (round, cushion, marquise) describes the outline of the stone from above, while cut describes the proportions and angles of the facets within that shape, regardless of which shape you choose.

How much can you realistically save by choosing a smaller stone with a better cut?

In practice, the difference can be tens of thousands of zlotys: in the Promise collection, the jump from 0.50 ct to 0.70 ct is an additional PLN 14,000, and a good cut in a smaller stone provides a similar visual effect.

Can a poor cut be improved after purchase?

No, the proportions of the cut are set once, when the rough stone is cut. Therefore, it's worth checking the cut grade on the certificate before purchase, rather than expecting improvements later.

Does every diamond shape have the same cut grading scale?

The Excellent to Poor scale primarily applies to the round brilliant cut. For other shapes, such as marquise or cushion, jewelers assess proportions more descriptively, without a single standardized GIA scale.

Where can I compare different cuts in person?

At the BELLER atelier at ul. Mokotowska 71 in Warsaw and at ul. Szczepańska 9 in Krakow, where a consultant will show several stones side by side in the same light.

This is one of those things worth knowing before, not after, purchasing, because a good cut is an investment in brilliance that stays with you forever. See our engagement ring collection or read more about BELLER certified diamonds. Related posts: what the 4Cs of a diamond are and how much to spend on an engagement ring.