The Four C's of Diamonds: Cut
A diamond's only job is to sparkle, and the sparkle is in the cut. Here's what cut means, why it's the C we'd spend on first, and the proportions to look for in a round diamond.
Two sides of cut
The simple side is shape: round, oval, princess and so on. If you haven't chosen yet, compare the diamond shapes.
The complex side is how well a diamond is cut for its shape. For every shape, cutters know the angles to cut, where the facets should meet and the proportions each facet should have, and today we can measure those facets very precisely.
Why cut matters most
A diamond doesn't have performance value like a car. Its only job is to sparkle, returning as much light as possible, and the cut is what makes it do that.
So why isn't every stone cut perfectly? Diamonds are products of nature, with imperfections, and every facet removes weight and value. A cutter often has to balance the quality of the cut against carat weight.
That's why cut is the C to protect. Take a so-so rough diamond and cut it perfectly, and it looks beautiful; take a top rough diamond and cut it poorly, and it looks like glass. If you're tempted by a poorly cut diamond just because it's cheaper, the person you're proposing to deserves better.
Professional diamond tip
A primer on the best cuts for round diamonds. On a GIA report, look for an Excellent cut grade; in the trade, Excellent cut, polish and symmetry is called "triple excellent." AGS's top grade is Ideal.
Ideal proportions for a round diamond:
Table: between 54% and 60%
Depth: between 58% and 62%
Anything within those ranges is best.
See what a great cut looks like
Two diamonds with the same grades can look completely different. We'll show you well-cut stones side by side so you can see the sparkle for yourself, in person in Downtown LA or by video call.
Explore the other C's
Each C trades off against the others. See how all four fit together, or read the next guide.
Let's find your diamond
Every Concierge Diamonds piece starts with a free, no-pressure consultation. The form takes about a minute, and we'll be in touch within two business days. Questions first? Read Dan Moran's answers on cut and the 4Cs or call (213) 261-4330.