‘Cut quality is the factor that fuels a diamond’s fire, sparkle and brilliance. The allure and beauty of a particular diamond depends more on cut quality than anything else.’ - GIA 

What is diamond cut?

The most important of the 4Cs, the cut grade refers to the overall cut quality and how the stones facets interact with light, creating what we see as the sparkle, brightness, and beauty of the diamond. This is determined by the stones' symmetry, proportion and polish.

The GIA grades the cut on a relative scale from Excellent to Poor.

it's important to note that the cut is the quality of the cut not the ‘shape’ of the stone.

Why is Diamond cut important?

If cut poorly the diamond will appear smaller, duller and less sparkly. A well-cut diamond will reflect and refract light resulting in a beautiful, bright and sparkly diamond.

Here at Mill & Way we specialise in only the highest quality stones. We only sell diamonds with the best quality cut as we want our customers to have the most beautiful diamonds.

What impacts the quality of a diamond cut?

Cut is responsible for the quality and level of a diamond sparkle.

The cut is responsible for how light strikes the surface of a diamond, how much light enters the stone and how and in what form light returns to the eye.

The cut is based on the assessment of seven components:

Brightness - Also known as the ‘Brilliance’ this refers to the total light reflected from a diamond and how bright the diamond appears.

Fire - The Dispersion of light into the colours of the spectrum.

Scintillation - the pattern of light and dark areas and the flashes of light, or sparkle, when a diamond is moved.

Polish - The detailed and placements of the facets as well as the overall finish of the diamonds surface.

Symmetry - How precisely the various facets of a diamond align and intersect.

Weight ratio and durability - otherwise known as the precision of the cut, this is based on the craftsmanship of the diamond.

Diamond cut chart:

Many jewellers will sell a range of cut grades including ‘poor’ cuts or will purposely choose not to inform their customer about the importance of the cut grade. Mill & Way refuses to compromise on quality by only selling excellent cut diamonds.

Diamond cut also refers to the shape and cutting style. There are many unique and wonderful diamond cuts but the most common is by far the round brilliant. Diamonds with shapes or cutting styles other than the round brilliant are known as fancy cut diamonds.


The brilliant cut is the most well-known facet arrangement, made of triangular and kite-shaped facets arranged to optimise the brilliance and light return.

Consisting of 57 to 58 facets the Round Brilliant diamond is the most popular shape for engagement rings. Oval, Pear, Cushion, Marquis and Heart-Shaped diamonds are also cut with a brilliant faceting style.


A Step-cut refers to a diamond with facets that run parallel to each other. The most popular step-cut design is the emerald cut.