Last Updated on 24th March 2025
Diamonds are a true testament that beauty radiates from the inside. And deep within the diamond’s makeup is, in fact, calculated beauty – precise cut proportions that produce the magical sparkle seen by the naked eye!
As long as you have excellent cut proportions, the diamond will look amazing in and out, right? Well, not entirely. To best showcase the brilliant cut, we also have to consider diamond polish. Because a poor polish will mask the diamond’s light return and ultimately compromise the superb cut.
So yes, the best diamonds are beautiful on the inside. But let’s also not forget about outer features such as the diamond polish. Although it’s not as vital as the Diamond 4Cs, it plays a part!
What is Diamond Polish?
The Diamond Polish refers to the finish done on the diamond’s surface after it has been cut. During the process, flaws may be created by the polishing wheel as it draws minute remnants across the surface. This is where the quality of the polish is graded.
Gemologists evaluate the smoothness of the surface under 10x magnification and rates according to how much imperfection can be seen with and without a loupe. If the polish marks are so severe, they may hinder the light that travels in the diamond.
So, what about the flaws inside? Such inclusions are already existent when the diamond was formed that’s why it’s graded under Clarity. Diamond polish belongs to the diamond cut features because the quality depends on how well the cutter was able to polish the diamond.
Which Diamond Polish Grade Should You Choose?
Polish Grade |
Example |
Description |
Excellent Polish |
 |
There are no polish flaws visible under a 10x loupe. |
Very Good Polish |
 |
Imperfections are very hard to see under a 10x loupe. |
Good Polish |
 |
Imperfections are hard to see under a 10x loupe. |
Fair Polish |
 |
Polish flaws can be seen under a 10x loupe and may be visible to the naked eye. Usually not offered by reputable diamond shops. |
Poor Polish |
 |
Flaws are visible to the naked eye. Usually not offered by reputable diamond shops. |
As you know, I’m a strong advocate of not compromising on the diamond cut. I think that if your budget allows for it, you should always go for an “Excellent/Ideal” cut grade.
GIA only gives an “Excellent” cut grade to diamonds with at least an “Excellent” or “Very Good” polish grade. Although in my 2-year experience working in a brick and mortar jewelry store, I could only distinguish “Excellent” and “Good” polish grades with difficulty and a 10x loupe.
The polish flaws of a diamond with a “Good” polish grade can rarely be made out with the naked eye. Thus, there might be diamonds that receive a “Very Good” cut grade due to the “Good” polish grade. In such a case in which the diamond’s cut grade is only downgraded because of a “Good” polish grade, it would usually still be advisable to go for this stone.
|
Excellent Polish – 1.00 CARAT G-VS2 EXCELLENT CUT ROUND DIAMOND |
Good Polish – 1.01 CARAT G-VS2 GOOD CUT ROUND DIAMOND |
What’s evident is that an “Excellent/Ideal” polish grade bears a very smooth surface that allows for the highest amount of brilliance, fire, and scintillation. While a diamond with a poor polish has a murky luster that can hamper the diamond’s light performance. If you’re opting for less than .75 carats, you may choose a Good polish grade. Fair and Poor polish grades are typically not recommended by top diamond stores.
Most customers are no diamond experts and might not know the specific reasons for which a diamond does not receive the best cut grade. You can always contact me, and I will be more than happy to help you out!
Factors that Influence the Diamond Polish Grade
The polish quality of a diamond is directly influenced by the polishing process. And a better polish grade is achieved by polishing for a longer time, and by using a better polishing wheel with diamond dust consisting of particularly fine grain.
Most flaws cannot be seen by the naked eye, but the most common ones are laid out below:
Polish Mark |
Visual |
Description |
Abrasion |
 |
An area of minute scratches or pits along a facet edge producing a fuzzy white line instead of a sharp facet junction. |
Burn |
 |
Whitish haze caused by excessive heat during polishing or, occasionally, by a jeweler’s torch is listed as “Brn.” A burn mark caused by excessive heat at the location where the dop touched the diamond is referred to more specifically as “Dop.” |
Laser Manufacturing Remnant |
 |
A remnant of laser manufacturing that remains on the surface of the polished diamond; typically appears as a transparent or white groove; only considered polish when it does not penetrate into the diamond at 10x magnification. |
Lizard Skin |
 |
A transparent, uneven texture confined to one facet caused by polishing a facet off-grain. |
Nick |
 |
A small notch on a facet junction, usually along the girdle or at the culet. |
Pit |
 |
A tiny opening appearing as a white dot. |
Rough Girdle |
 |
An irregular pitted or granular surface of a bruted girdle due to pits and nicks. |
Scratch |
 |
A surface mark, normally seen as a fine white line that may be curved or straight. |
Polish Lines |
|
Parallel lines left by the polishing process; may appear white (Wht) or transparent (TP). A heavy transparent polish line off a surface-reaching feature is referred to more specifically as a “drag line”.
A surface feature made during the polishing process that resembles an extra facet without a distinct or straight facet junction is referred to as a “polish mark”. |
The Bottomline
A diamond’s polish grade does affect its overall cut grade. But the cut itself is far more important! The reason is simply that only an “Excellent” cut grade makes sure that the crown and pavilion angles and the other proportions of a diamond are best suited for refracting the light in the most brilliant way.
In great part, it is the exact angles and proportions of a diamond that determine its light performance. Thus, if you are faced with a choice between better diamond polish or better cut, I would strongly advise going for the better cut proportions.
Many people want to have an “Excellent” grade in cut, symmetry, and polish, and this is fine for ideal purposes. Although you can get a better bang for the buck with the same quality if you choose a “Very Good” polish grade. I guarantee that, in such a case, your diamond will look beautiful inside and out!
Should you have questions, please feel free to write to me or comment down below!
My advice is free. 🙂