The cut of a diamond refers to its angles and proportions, and it determines its beauty. The skill of the diamond cutter determines how well it reflects and refracts light.

Polish describes the finish of a diamond's facets and is graded from Ideal to Poor. Good or higher polish grades have little impact on a diamond's brilliance and are ideal for high-quality jewelry. Some gem labs, like Gemscan, include polish when grading a diamond's overall cut.

Length-to-Width Ratio: Shows diamond elongation from top. Personal preference varies. Popular ratios listed below for fancy shapes."

Determines facet alignment. Graded from Ideal to Poor. Good+ grades suit premium jewelry. Some labs include Symmetry in the Cut grade, e.g. Gemscan.

The top facet of a gemstone is the table. Its width is expressed as a percentage of the girdle diameter, known as table %.

Diamond height, from culet to table. Depth % is height as % of girdle diameter.

The Diamond Stock Number is the unique identifier assigned to each diamond.

Laboratory reports are critical for diamond grading, determining value and authenticity. The GIA or IGI offer grading reports for diamonds, detailing the 4Cs: carat, color, clarity, and cut.