Diamond Cut Guide
Where Sparkle Meets Precision
Cut is the most important of the 4Cs. It decides how brilliantly a diamond reflects light. A well-cut diamond shows fire, brilliance and scintillation, even with average clarity or colour.
Cut is more than shape. It’s how well the facets work with light: proportion, symmetry and polish. That’s what brings a diamond to life.
Cut Grades Explained
Cut grades apply mainly to round brilliant diamonds, as this shape is graded most precisely. The most widely used scale is:
| Grade | Description |
|---|---|
| Excellent | Maximum fire, brilliance and sparkle |
| Very Good | Exceptional sparkle with slight differences in proportions |
| Good | Still attractive, but may lack some light performance |
| Fair | Noticeable dullness or less efficient light return |
| Poor | Lacks sparkle; light escapes through the bottom and sides |
The Real Gem tip: choose an Excellent or Very Good cut for the best sparkle, especially in an engagement ring.
The 3 Elements of Sparkle
- Brilliance: white light reflected from the diamond
- Fire: the rainbow flashes of dispersed light
- Scintillation: the sparkle as the diamond moves
A well-cut diamond balances all three.
Why Cut Matters Most
Even a large, high-clarity diamond can look dull with a poor cut. A smaller diamond with an excellent cut will often look larger and brighter.
Cut is the only one of the 4Cs shaped entirely by human skill, which is why we pay close attention to it.
How We Choose
We choose well-cut stones with strong light return, and we’re happy to talk you through the cut of any piece before you buy.
Cut and Price
Cut affects price, but it’s worth it. A diamond with an excellent cut can outshine more expensive stones with higher colour or clarity.
The Real Gem tip: if in doubt, put more of your budget into cut than the other Cs. It’s what your eye notices most.