Diamond Cut

Q: What’s the best diamond cut?

For round diamonds, Excellent or RC Ideal cut delivers maximum sparkle. For fancy shapes (oval, pear, cushion, etc.) GIA doesn’t issue an official cut grade - look for our “RC Ideal” flag, which scores proportions and light performance with our AI.

Q: Is cut more important than carat?

For visual beauty, yes. A well-cut smaller diamond outshines a poorly-cut bigger one. Cut decides whether a stone looks alive or lifeless - no other C compensates.

Q: What’s the difference between cut and shape?

Shape is the outline (round, oval, pear, etc.); cut is the craftsmanship within that shape - facet angles, proportions, polish, and symmetry. Every shape can be cut Excellent or Poor.

Q: Why do fancy-shaped diamonds not have an official cut grade?

The GIA only issues a cut grade for round brilliants - they’re mathematically the most studied shape. Other shapes are evaluated on polish and symmetry but not overall cut. That’s why we use our own AI to assign an “RC Ideal” cut quality across every shape.

Q: Will a thicker pavilion make my diamond look bigger?

No - it hides weight underneath rather than spreading it across the top. That makes the diamond weigh more without looking bigger. Always check millimeter dimensions next to carat weight.

Q: How does cut affect price?

A jump from Very Good to Excellent or RC Ideal cut typically adds 10–20% to the price. Cut is the C we recommend never compromising on - the visual return on those extra dollars is the highest of any C.

If you prioritize one of the 4Cs, make it cut. Cut determines how a diamond handles light - its brilliance, its fire, and the scintillation you see as the stone moves.

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01.
Why cut matters most
02.
Cut grades
03.
Anatomy of a cut
04.
Cut vs. shape
05.
FAQs

01.Why

Cut is the single biggest factor in how beautiful a diamond looks

Color, clarity, and carat decide what a diamond is. Cut decides what a diamond does: how much light it captures, how that light bounces back, and whether the stone reads as alive or dead from across a room.

A poorly cut D-Flawless 2-carat will look duller than a well-cut H-VS2 1-carat, and cost a lot more.

Three things show up in a well-cut diamond: brilliance (white light return), fire (the rainbow flashes), and scintillation (the sparkle as the stone moves).

The light return

RC Ideal

Rare Carat Ideal Cut

A well-cut diamond catches and returns light evenly across its entire surface.

02.Grades

The five cut grades, and where the value is

The GIA grades cut on five tiers: Excellent, Very Good, Good, Fair, and Poor. Rare Carat adds an even higher tier - RC Ideal - for diamonds whose proportions and light performance test exceptionally well.

RC Ideal: the best of the best. Maximum brilliance, fire, and scintillation across the entire stone.

Excellent: indistinguishable from Ideal face-up to most eyes. The most popular option.

Very Good: still beautiful sparkle with minor proportion compromises. You can often get great value here.

Good: noticeably less light return. Fine for accent stones, less ideal for a center stone.

Fair / Poor: we don’t recommend either as a center stone. The light loss is visible.

Diamond Cut Chart

The best of the best. Maximizes brilliance, fire, and sparkle with perfect proportions.

Good

Very Good

Excellent

RC Ideal cut

Learn more about diamond cut

03.Anatomy

What cutters are actually adjusting

Cut grading is an evaluation of three properties. First, a quick definition: a facet is one of the small, flat, polished surfaces that cover a diamond - a round brilliant has 58 of them. Cut grading measures how well those facets are shaped and arranged:

Proportions - the angles and sizes of each facet, especially the table (top), crown (slope from table to girdle), pavilion (slope from girdle to point), and depth (overall height). Get these into a narrow range and light enters and exits the diamond cleanly.

Polish - the surface smoothness of every facet. Poor polish scatters light and dulls the brilliance.

Symmetry - how precisely each facet aligns with its opposite. Poor symmetry steers light at uneven angles, producing dim or dead spots.

A well-cut diamond gets all three right at once. That’s the craft.

RARE CARAT PRO TIP

Fancy shapes (oval, pear, cushion, marquise) don’t receive an official GIA cut grade - only round diamonds do. That’s where our AI comes in: we analyze proportions and light performance for every shape and surface the “RC Ideal” stones automatically.

Three properties at once

Proportions - table, crown, pavilion angles
Polish - facet-surface smoothness
Symmetry - opposing-facet alignment

Focus on all three of these to maximize brilliance.

Or browse by cut grade

04.Shape

Cut vs. shape - they’re not the same thing

Shape is the outline: round, oval, princess, cushion, emerald, pear, marquise, radiant, asscher, heart.

Cut is how well the diamond was faceted within that outline. A round diamond can be cut Excellent or Poor; so can an oval diamond.

The two interact: brilliant-faceted shapes (round, oval, pear, cushion, radiant) hide inclusions and color better. Step-faceted shapes (emerald, asscher, baguette) are more demanding - they need higher color, higher clarity, and stellar cut.

Don’t confuse a popular shape with a guaranteed cut. Every shape comes in every cut quality - and the gap between a great cut and a mediocre cut, within the same shape, is enormous.

Every shape, every cut

Round

Oval

Princess

Emerald

Pear

Shape is the outline. Cut is the craftsmanship inside it. Both matter - for very different reasons.

Or browse every cut grade

What’s the best diamond cut?

Is cut more important than carat?

What’s the difference between cut and shape?

Why do fancy-shaped diamonds not have an official cut grade?