Diamond Education

Diamond Polish and Symmetry Grading Guide

Diamond Polish and Symmetry Grading Guide

The best gemstone experts carefully study the rough diamond before cutting it. They look at the grain, any mistakes, and the exact dimensions. Then they decide how best to express the beauty in that particular stone, using diamond symmetry, proportion, and diamond polish.

Diamond Symmetry

The most beautiful diamonds are perfectly symmetrical. It means that all facets on either side are identical to the facets directly opposite. The symmetry of a diamond is determines by the different proportions. A diamond should remain within the agreed dimensions. If not, it will affect the brilliance of the diamond. The symmetry of a diamond is also qualified as excellent, very good, good, or fair. Most diamonds are of good quality and fit within the proportion profile the symmetry of a cut is stated on the certificate.

What Does Diamond Symmetry mean?

Symmetry Diamond

The symmetry relates to the precision, shape, and arrangement of the diamond facets. The brilliant cut z. B. has 58 (or 57, if he does not have the one at the bottom, the culet), which must be perfectly symmetrical: it is not easy. We have to say that identifying symmetry is not easy: the Gemological Institute of America (GIA) took 15 years to study 38 million diamonds before deciding how to judge the symmetry of a diamond, especially the round, brilliant cut. At the end of so much effort, the parameters and classification have been established. The symmetry can be excellent, very good, good, fair, or bad.

Because it’s important of diamond symmetry

Think about it: a diamond should be as transparent as possible to let light inside. Then it has to reflect the light via its facets. If these are not perfectly symmetrical, the shine of the light will not be perfect either. What’s more, the diamond could trigger very little because the stone cannot find out the light from within. It happens often? Fortunately no. Some time ago, those who cut the stones all cut by hand, in poorly lit environments. Well, that technology helps avoid mistakes, or almost.

Diamonds: Be careful about symmetry

Beware of symmetry: the cut of a diamond can improve it or make a less brilliant ring. Here’s how to find out. While you are ready to invest some of your savings in a diamond ring, think about how to choose the jewel.

Of course, a diamond is forever: for this reason, it is worth making a careful choice. You already know what the four C’s are. You have already read our guide on How to Choose the Diamond Ring and How to Make a Diamond. But there’s one more thing to know: you need to look for symmetry. Yes: a diamond can also be a little flawed. In this case, it will shine less and be of less value in the future.

What is the Diamond Polish?

Diamond Polish– One of the last steps in the sharpening process is polishing. The cutting of the diamond causes small irregularities on the surface of the gemstone and these irregularities to hinder the reflection of light. Diamonds are polished with diamond dust and other abrasives to make the surface smooth. In this way, the light enters the stone and is reflected outside without any obstacles.

Experienced gem experts pay attention to the symmetry, proportions, and polish of every well-cut diamond, but at 1% they redouble their efforts to create the heart and arrow-shaped diamonds.

What is the meaning of Hearts and Arrows?

Hearts and arrows Diamond

The Japanese were the first to create a heart and arrow-shaped diamonds in the 1980s. Japanese jewelers optimized the symmetry of the diamond, changed the facet pattern, and took extra time to diamond polish the stones. The result was an exceptional diamond with eight internal symmetrical arrows when viewed from above, and eight internal symmetrical hearts when viewed from below.

Hearts and arrows Diamond

Today hearts and arrows diamonds are made by jewelers all over the world. They cost more than the round brilliant diamonds, but they are well worth the investment: they are exceptionally brilliant and the hearts are hidden inside provide the extra allure.

Symmetry Grading – Operating a Round Brilliant Cut Diamond As an Example

The grading process for symmetry can be further sub-dividing into two types of categories – Proportions and Facets related.

The alteration of the symmetry which impacts the alignment and balance of a diamond’s facet structure is considered a proportioning flaw. These flaws are usually measurable and impact the diamond’s overall appearance. Read below the best example:

Today’s round brilliant cut diamonds have 58 facets if a collet was added, 57 without a collet. The experts have names different types of facets so that they can be very specific in their work. On the crown of a diamond, around the table, we find the star (star), kite (kite), and higher girdle (upper girdle) facets. The lower girdle and pavilion facets extend from the girdle to the underside of the diamond. If a collet was adds, this is the bottom or lowest facet.

Diamond Symmetry Graded, Just Like the 4Cs of Diamonds

Diamond Symmetry Graded, Just Like the 4Cs of Diamonds


No features or features that is difficult to see fewer than 10 x magnifications.

Very Good:

Small deviations and symmetry features under 10x magnification.


Several symmetry features, visible under 10x magnifications, can influence the brilliance and appearance of the diamond.


Several, more pronounced symmetry deficits. Fire and brilliance are likely to be impairs.


Numerous severe features that affect the appearance of the diamond. Symmetry deficits can be seen with the naked eye.

Diamond Polishing Graded, Just Like the 4C’s of Diamonds

Excellent (excellent):

No to very few, small polish features that are difficult to see under 10x magnification. The degree of purity “FL” shows no characteristics.

Very good (very good):

Small polishing marks are visible under 10x magnification.

Good (Gut):

Polish features are easily recognizable under 10x magnification. This is where the diamond’s “luster” can be impairs when viewed with the naked eye.

Poor (Little):

Heavy polishing marks that affect the “luster” and overall appearance of the diamond.

Diamond Symmetry Features Found on a Diamond

The following two include features found on the diamond;

Small Symmetry Deficits: 

  • The facets do not meet or have unequal shapes
  • The board is not completely octagonal
  • Extra Facet
  • A slight deviation from the round / circular shape
  • Slightly eccentric table or culet
  • Slightly wavy girdle

Serious symmetry features:

  • Deviation from the circular shape that can be seen with the naked eye
  • See with the naked eye: Board not parallel to the girdle
  • Strongly eccentric table or culet
  • Strongly wavy girdle (extremely sharp to very thick)

Common Polish Features Found on a Diamond

Basically every diamond (except for flawless stones) has some remains of polishing marks on its surface. In the case of a diamond with an “excellent” polish rating, the polish lines are so good that they can only be seen under high magnification and through a specific tilt angle.

When (GIA) Gemological labs consider a diamond for its polish rating, they examine the facets for surface blemishes such as:

Diamond Polish Features

Polishing Strips: White to transparent, parallel lines, Limited to one facet.

Scratch: White, curvy, or straight single line.

Abrasion / Fringed spots: Facet edge with several small scratches or notches.

Pit: Small bumps, seen as a white point.

Nick: Features on the facet edges of the girdle or the culet caused by blows or bumps. Flaking with no discernible depth.

Additional facets: The grinder can deviate from the standard number of facets if this removes a natural or other feature.

Last Opinion about Diamond Symmetry and Polishing is More Important

Diamond symmetry and diamond polish can both significantly affect the beauty, quality, and price of a diamond. But this last but not least step its important when you are buying a diamond online knows that the only thing that issue about a diamond’s polish and symmetry is that you are happy with it.

If having a diamond (whether it’s for your engagement ring, a wedding ring, classic diamond ring, diamond tennis bracelet, stud earrings, or another piece of diamond jewelry) that is symmetrical and free of blemishes to the naked eye is significant to you, you will likely want to go with symmetry and polish grades of Very Good or higher. Next, if you think that you would be good with a few small imperfections or more perceptible imperfections, you can always choose a diamond with less polish or symmetry grades.

It may appear like there is too much to know about diamonds if you’re just beginning, but if you take the time to educate yourself, you’re sure to find a beautiful diamond and at the most reasonable price at our Gemistone Jewelers online store!

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