Diamond Cut: Why It Matters More Than Any Other C
When people say a diamond sparkles, they are describing cut. Not the shape, which is the outline of the stone, but how precisely its facets are angled to catch and return light.
Cut is graded, and the grade matters more to what you see than color or clarity. It is the one C where we tell every customer not to compromise.
Cut and shape are different things
Shape is the silhouette: round, oval, princess, emerald, and so on. Cut is the quality of the workmanship inside that shape. You can have a beautifully cut oval and a badly cut one, and they will look like different stones.
What the light is doing
Light enters through the top of a diamond, bounces between the facets, and exits back through the top. When the angles are right, you get three effects: brightness (white light returned), fire (flashes of color), and scintillation (the pattern of sparkle as the stone moves).
When the stone is cut too deep or too shallow, light escapes through the bottom or sides instead. A too-shallow stone can show a dull ring in the middle. A too-deep stone looks smaller than its weight and dark in the center.
Reading the cut grade
Round brilliant diamonds get an overall cut grade, usually Excellent, Very Good, Good, Fair, or Poor. Stay in the top two. The price difference between Excellent and Very Good is often modest, and both perform beautifully.
Fancy shapes do not get a single cut grade, which trips a lot of buyers up. For ovals, pears, and marquises, watch for a bow tie, a dark band across the middle of the stone. Every elongated shape has some; a good one keeps it faint.
How to judge cut yourself
- Look at the stone under normal light, not just jewelry-store spotlights.
- Tilt it. A well-cut stone keeps sparkling at an angle; a poor one goes glassy.
- Compare two stones side by side. Differences that sound small on paper are obvious in person.
- For fancy shapes, ask to see a video of the exact stone, not a stock photo of the shape.
Common questions
Is Excellent cut worth the premium over Very Good?
Sometimes. If the two stones look the same to you side by side, take the Very Good and put the savings into size or color. If the Excellent stone visibly outperforms, it is worth it. This is exactly the comparison we set up for customers in the store.
What are hearts and arrows diamonds?
A round diamond cut with such precision that a symmetrical hearts-and-arrows pattern shows under a special viewer. They command a premium. Beautiful, but an ordinary Excellent cut gives you most of the performance for less.
