What Are Diamond Cuts?
Cut describes how a diamond is shaped and polished, and how its facets return light to your eye. A well-cut diamond looks bright and lively, even in ordinary room light.
Cut is not the same as shape. Shape is the outline of the stone, such as round or oval. Cut is how well that outline is proportioned and finished.
How Are Diamonds Cut and Graded?
A rough stone is planned, cleaved or sawn, shaped, and polished in stages. Each stage is judged on proportions, symmetry, and polish, because a small change in angle can change how light travels through the stone.
Grading reports summarize cut on a scale from excellent to poor. Always ask for the grading report for the specific stone, not only the general grade for a collection.
Anatomy of a Diamond Cut
The top of the stone is the table and crown, the narrow edge is the girdle, and the bottom is the pavilion ending in the culet. Depth is the total height from table to culet, compared with the width of the stone.
| Part | What it does |
|---|---|
| Table | The flat top facet where light enters. |
| Crown | The upper part above the girdle. |
| Girdle | The narrow edge around the widest part. |
| Pavilion | The lower part below the girdle. |
| Culet | The small point or facet at the bottom. |
| Depth | The total height from table to culet. |
Diamond Cut Quality Factors
Appearance covers brilliance, fire, and scintillation. Brilliance is the white light returned to the eye, fire is the flashes of color, and scintillation is the sparkle you see when the stone moves.
Design covers proportions and angles. A stone that is too shallow leaks light through the bottom, and a stone that is too deep traps light so the center looks dark.
Craftsmanship covers symmetry and polish. Well-aligned facets and a smooth polish let light travel cleanly, while poor symmetry or rough polish can dull the stone.
Diamond Cut Grades
Cut grades run from the highest to the lowest. The top grades return the most light, while lower grades show visible dullness or dark areas in normal light.
| Grade | What to expect |
|---|---|
| Super Ideal | The most precise proportions and symmetry, with maximum light return. |
| Ideal | Excellent light return, with proportions at the top of the standard range. |
| Very Good | Strong light return, with a small compromise in proportions. |
| Good | Good light return, with a noticeable compromise in some stones. |
| Fair | Visible dullness or dark areas in normal light. |
| Poor | Significant light loss, with a dull or dark appearance. |
Different Types of Diamond Cuts
Round brilliant cuts are the classic choice for maximum sparkle, with a symmetrical facet pattern designed for light return.
Fancy cuts include modified brilliant cuts, which mix brilliant and step facets; step cuts, with long parallel facets and a calm, architectural look; rose cuts, with a flat base and a domed top; and vintage cuts, which echo older cutting styles with larger facets.
How Does Diamond Cut Impact Price?
Better cut usually costs more, because it takes more time, more skill, and often more rough material to achieve. A well-cut stone can also look larger and brighter than a poorly cut stone of the same weight.
If your budget is tight, a very good cut often gives most of the sparkle of the top grades at a lower price. Compare stones side by side in similar lighting before you decide.
Diamond Cuts Guide FAQ
What is diamond cut?
Cut describes how a diamond is shaped and polished, and how its facets return light. It is one of the 4 Cs, alongside color, clarity, and carat.
What is the difference between cut and shape?
Shape is the outline of the stone, such as round, oval, or emerald. Cut is how well that outline is proportioned, finished, and polished.
Is cut the most important of the 4 Cs?
Cut usually has the greatest impact on sparkle, but the right balance depends on your priorities, budget, shape, and setting.
What are the cut grades?
Common grades run from super ideal and ideal at the top, through very good and good, to fair and poor. Higher grades return more light.
Which cut is the most brilliant?
Round brilliant cuts are generally the most brilliant, because their facet pattern is designed for maximum light return.
Which cut is the most popular?
Round is the most popular shape, followed by oval and cushion. Popularity varies by year and by setting style.
What is a bow-tie effect?
A bow-tie is a dark, bow-shaped shadow across the center of some oval, pear, and marquise stones. It is caused by light leaking through the stone, and it is more visible in some cuts than others.
Does cut affect price?
Yes. Better cut usually costs more, because it takes more skill and more rough material. A very good cut often gives most of the sparkle at a lower price.
What does a diamond look like before it is cut?
A rough diamond looks like a dull, cloudy crystal. Cutting and polishing are what reveal its brightness and fire.
How do I choose a cut grade on a budget?
Start with very good or ideal, compare stones in similar lighting, and put the remaining budget toward the shape and setting you like most.