Symmetry refers to the exactness of the shape and arrangement of facets in a diamond. Although to the naked eye polish has only a small effect on appearance, symmetry has a significant effect.

Crown & Pavilion Misalignment – In a round diamond the top points of the pavilion mains and the bottom points of the bezel facets should meet precisely at the girdle.

Table & Girdle Misalignment – – the table is not parallel with the girdle. As you see, the crown angle is much steeper on one-side versus the other. From the top view you may have noticed an off-center table.

Misshapen Facet – A correct table displays a regular octagonal shape. It should have eight sides of equal length that are each parallel to the opposing opposite facet. In this example we see facets that are not the same size and shape as others like them on the face of the diamond.

T/OC Table Off–Center The placement of the table (the largest facet on a diamond) should be centered at the top of the stone and needs to be parallel to the girdle. If the table is off-center or not parallel with the girdle this can cause uneven crown angles from one side to the other.

C/OC Culet Off-Center – To check if the culet is centered look at the diamond in the face-up position. You’ll see the lower girdle facets through the table. If the lines formed by them look like a perfect square, the culet is centered. If the cross bends one way or the other, the culet is not centered. In this example we see what an off-centered culet might look like

Extra Facets -These are typically located on the pavilion, near the girdle, but they can be found anywhere on a diamond. In this example we see where extra facets commonly occur.

Crown Height verification– Contrary crown height measurement may indicate about a wavy girdle or crown – pavilion misalignment.

Crown angel verification – Unequal crown angel measurement may indicate a wavy girdle or crown – pavilion misalignment.

Pavilion Depth verification – dissimilarities in pavilion depth is a sign of a wavy girdle.

Pavilion angel verification – Differing crown angel indicate for culet of center (COC).

Wavy Girdle – The girdle of a diamond should be a flat plane, parallel to the table. In this example the girdle “waves” as it wraps
around the diamond.

Faces not Pointing Up – Some diamonds display facets that are not properly pointed. Facet patterns of round brilliants are meant to show a precise arrangement of 58 perfectly shaped facets. In this example we see some that some do not meet at a direct point.

Naturals on Crown and Pavilion – A natural is the original “rough” of the diamond. Naturals always occur or start out on the girdle. They either dip towards the pavilion or the crown. In this example we see the natural located on the girdle running down into the pavilion.

The quality of a diamond’s polish can affect the way light enters and is refracted from the stone. Polishing removes unwanted material by gradual erosion. After polishing, the diamond is re-examined for possible flaws, either remaining or induced by the polishing process.

This characteristic refers to the finishing or final polishing of the facets, or flat surfaces. Each facet should be carefully fashioned by the diamond cutter to shine and be free from polishing imperfections that can dull the diamond. The polish of a diamond is generally defined as: Poor, Fair, Good, Very Good, or Excellent. When purchasing a diamond, generally the rarer color and clarity diamonds are also well polished. Contrary to common belief, diamonds are ground and polished, not chipped away, until they reach their final form.

Cut identify how closely the diamond has been cut and polished to ideal proportions.
A diamond’s cut is not only about its shape, but how effectively the stone can return light back to the viewer’s eye. A well-cut diamond will be seen as brilliant and sparkling. A poorly cut diamond may have the highest color and perfect clarity yet it will look dark and lifeless.
Not only do well-cut diamonds appear more brilliant, they can also appear larger than other stones of the same carat weight. An ideal stone has both increased brilliance as well as increased diameter relative to more deeply cut diamonds.

When a diamond is cut to the proper proportions and is finished well, light refracts into the diamond, is reflected from one facet to another and then returns through the top of the gem resulting in a display of brilliance (white light), dispersion (rainbow-colored light) and scintillation (sparkling when the diamond moves), and luster (bright reflections from the surface). Proper cutting is the key to a diamond’s beauty and value.
Most diamond shapes are cut with 58 facets, or separate flat surfaces, according to mathematical formulas. Using symmetry, the cutter aligns these facets at precise angles in relation to each other to maximize the reflection and refraction of light.

The proportions are calculated in angles & percentages that show how well the diamond refracts and reflects light.

To understand the sub-categories for well-cut diamonds, think of a pyramid with “Ideal” at the top. This narrow range is reserved for the most brilliant, rare and valuable diamonds. The “Excellent” range includes beautiful diamonds that return almost as much light. “Very Good” represents the balance between precise proportions and price considerations.

Each Diamond Part Has A Function:
Crown: Balance, Brilliance, Dispersion, and Scintillation
Girdle: Provide a Setting Edge for the gem
Pavilion: Reflect light back up through the crown
Culet: Prevent Chipping at the tip