How a diamond makes the "cut"

We may usually think of a diamond's "cut" as its shape - oval, round, pear, heart etc. But in professional terms, the cut of a diamond is how well it was polished, and the magnitude of its sparkle.

We can determine how well a diamond is cut. The industry standard, GIA (Gemological Institute of America), assigns the following scale:

GIA diamond cut scale

When you are buying engagement rings or diamond jewellery, you may come across a diamond grading report from GIA. There are 3 elements:

1. Shape and cutting style: Shape means round, oval, pear, heart etc. Cutting style is the facet arrangement. Usually for a round brilliant diamond, there are 57-58 facets.

2. Polish: This grade determines if the surface of a diamond is polished smoothly, or if there are blemishes and uneven surfaces. It can range from Excellent to Poor.

3. Symmetry: When a diamond is being cut and polished, the facets should be of equal size and dimensions. Perfectly cut diamonds have the Excellent grade, while diamonds with facets of different sizes are graded Poor.

When you see triple Excellent or Ex Ex Ex, it means the diamond is of the highest quality cut, meaning it is Excellent in its cutting, polish and symmetry. Diamonds with triple Ex are usually more valuable as the diamond sparkles more.

Diamond cut

Sources: GIA