Cut

Diamond cut means how well a diamond’s facets (flat surfaces cut onto a gemstone and arranged in a geometrical pattern) interact with light to create desirable visual effects. Of all the diamond 4Cs, Diamond cut is the most complex and technically difficult to analyse and grade.

The description of the Cut Grade on a grading report is subdivided into: Cut grade, polish and symmetry. Each of these are graded into 4 categories: Excellent, Very Good, Good, and Fair.

Cut grade

In Cut grade, the proportions of the facets of a round diamond are evaluated for ‘brightness’ (Internal and external white light reflected from a diamond), ‘fire’ (the scattering of white light into all the colours of the rainbow) and ‘scintillation’ (the amount of sparkle a diamond produces).

Cut grades are only given to round diamonds and not to "fancy shapes" (shapes other than round, like oval, cushion, etc.)

Polish

In polish the quality of polish on the diamond facets is checked.

Symmetry

In symmetry, the diamond is graded based on how precisely the various facets of a diamond align and intersect.

Diamond cut and shape are often confused and used interchangeably, but they are two distinct concepts.

Diamond cut means how well a diamond’s facets interact with light, and it refers to a diamond's reflective qualities, proportions and symmetry. Diamond shape refers to a diamond's overall outline or external appearance when viewed from above. It is the very first thing the eye notices.

The round brilliant-cut diamond is the most popular and traditional shape. The diamonds of other shapes are called fancy-shaped diamonds. Examples of fancy shapes are princess cut, emerald cut, cushion cut, Asscher cut, pear cut, heart cut, oval cut, marquise cut, baguette cut, and radiant cut diamonds.

The fancy-shaped diamonds are popular in engagement rings. If you want a beautiful and distinctive design, you can choose shapes such as octagonal diamonds, trapezoids, half-moon, and trillion-cut diamonds.