When it comes to diamonds, polish is one of the most important characteristics to consider. The polish refers to the smoothness and symmetry of the diamond’s facets. A well-polished diamond will sparkle brilliantly, while a poorly polished diamond can look dull and lifeless. For customers looking to get the most out of their diamond purchase, polish should certainly be taken into account.
What is diamond polish?
Diamond polish refers to the smoothness and symmetry of the diamond’s facets. Facets are the tiny, geometrically-shaped surfaces that are cut into the diamond when it is polished. The number, alignment, and angles of these facets are precisely calculated to maximize brightness and “fire,” the rainbow sparkle you see when light reflects off a diamond.
When a diamond is well-polished, the facets will be highly reflective, symmetrical, and smooth to the touch. Each facet will be cleanly cut and aligned at the proper angle to allow light to refract and reflect off the diamond in a dazzling way. On the other hand, a poorly polished diamond will have facets that are uneven, scratched, or not aligned correctly. This prevents light from interacting with the diamond in the desired way, reducing its brilliance.
How is diamond polish evaluated?
There are a few key factors that professional diamond graders look for when evaluating the polish of a diamond:
- Smoothness – The facets should not have any nicks, scratches, or abrasions visible under 10x magnification. Any surface irregularities will reduce light reflection.
- Reflectiveness – Light should strongly reflect off the surface of the facets. Dull spots indicate issues with the polish.
- Symmetry – Facets on one side of the diamond should be precisely aligned with corresponding facets on the other side. Misaligned facets create an uneven look.
- Meet Points – The intersections where facets meet one another should form perfect points, not rounded edges.
- Girdle – The outer edge where the diamond’s top and bottom meet should be smoothly polished without any irregularities.
Diamond grading reports from independent labs like GIA will provide an overall polish grade ranging from Excellent to Poor. Diamonds with higher grades will have superior facet quality in the categories above.
How does polish impact a diamond’s appearance?
Diamond polish has a very direct impact on the stone’s visual performance. Well-polished diamonds exhibit exceptional brilliance, fire, and scintillation:
- Brilliance – How bright the diamond is when light reflects off the facets. A highly polished diamond will be extremely brilliant.
- Fire – The flashes of rainbow colors you see when light disperses through the diamond. Proper facet angles maximize fire in a polished diamond.
- Scintillation – The sparkling flashes of light you see when the diamond, light source, or viewer moves. Smooth, symmetrical facets create optimal scintillation.
Conversely, diamonds with poor polish appear dark, lifeless, and lack visual interest. The light performance of such diamonds is severely compromised. Even small polish issues like minor scratches and abrasions can reduce brilliance and sparkle.
How important is polish for different diamond shapes?
Polish is important for all diamond shapes, but it is especially critical for shapes with more facets, like round brilliant and princess cuts. These complex cuts rely on precise, symmetrical faceting to achieve their visual effects. Any polish irregularities are readily apparent.
Even diamonds with simpler cuts like emerald and Asscher still require proper polish to avoid a dull, flat appearance. While minor polish issues may be less obvious in these shapes, they will still detract from beauty and value compared to a very finely polished stone.
Importance of polish by shape:
| Diamond Shape | Importance of Polish |
|---|---|
| Round Brilliant | Extremely important |
| Princess | Extremely important |
| Cushion | Very important |
| Emerald | Moderately important |
| Asscher | Moderately important |
| Radiant | Very important |
| Oval | Very important |
| Pear | Very important |
| Marquise | Very important |
| Heart | Very important |
How does polish impact the value of a diamond?
Polish has a significant influence on a diamond’s value and pricing. Diamonds with Excellent polish ratings command substantially higher prices compared to stones with lower polish grades. All else being equal, a well-polished diamond will be worth 20-40% more than a comparable diamond with Poor polish.
For diamonds being considered for engagement rings or other fine jewelry pieces, Excellent and Very Good polish grades are recommended. These indicate facet quality sufficient to produce optimal sparkle and fire. Polish rated Good or lower often appears noticeably dull by comparison and is not desirable for important diamonds. The difference in visual performance is apparent even to untrained eyes in many cases.
That said, collectors interested in very large diamonds of over 10 carats may occasionally accept diamonds with Good polish to prioritize size over polish. Given the extreme rarity and cost of such large stones, acquiring sufficient polish is more difficult. However smaller, jewelry-quality diamonds should always exhibit Excellent or Very Good polish for best value.
Can poor diamond polish be remedied?
In some very limited cases, minor polish issues can be improved through expert re-polishing. This involves taking the diamond through the polishing process again to smooth out scratches or re-cut misaligned facets. However, re-polishing has strict limitations:
- Only small improvements possible – Cannot change overall quality tier (Good to Excellent)
- Causes further weight loss – Diamond gets smaller to fix issues
- May introduce new polish problems – Tricky to re-polish perfectly
- Not feasible for all diamonds – Based on location of damage, quality of material etc.
Because re-polishing reduces the diamond’s carat weight and may not fix severe issues, most diamonds with significant polish problems cannot be improved. Re-cutting the diamond into a different shape entirely is sometimes the only option, but results in an entirely new diamond.
For this reason, it is best to simply select a diamond with excellent Polish in the first place, rather than trying to correct a poorly polished diamond after the fact. No amount of re-work can make up for inherently poor facet symmetry and surface quality.
How can you verify the polish quality?
There are a few options for checking the polish quality of a diamond you are considering:
- Review grading reports – Reports from GIA and other labs provide polish ratings you can reference.
- Examine in person – Look at the diamond under a loupe or microscope for scratches, meet points, etc.
- Request idealscope images – These special photos show light spread to reveal polish issues.
- Compare videos – Look for dull spots, flair, and inconsistent sparkle.
- Return policies – Only buy from retailers with generous return policies, in case the diamond’s polish does not live up to expectations.
The most reliable way to verify polish is to personally inspect the diamond under magnification. High resolution videos and scope images can also reveal a lot. If purchasing online without access to the diamond, be sure to understand the retailer’s policies around returns and inspection periods.
Tips for maximizing diamond polish
Here are some tips for getting a diamond with ideal polish:
- Set polish as a priority – Sacrifice on less visible factors like color first.
- Only buy Very Good or Excellent – Check grading reports for the top two polish ratings.
- Select ideal proportions – Well-cut diamonds show off polish best. Avoid extremes.
- Choose round or symmetrical shapes – Visibility of poor polish minimized in simpler cuts.
- Examine locally – Inspect diamonds in person instead of relying on videos and photos.
- Buy from trusted dealers – Reputable sellers provide genuine polish grades and fulfillment.
Keeping polish as a primary consideration when shopping for a diamond, along with cut quality, will help you secure a stone with maximum sparkle potential.
Conclusion
In summary, diamond polish has a critical impact on the overall visual performance and value of a diamond. Excellent polish results in unmatched brilliance and fire, while poor polish severely detracts from sparkle and beauty. For jewelry buyers and collectors alike, polish should always be evaluated carefully along with the other Cs when selecting a diamond. While polish flaws can occasionally be minimized through re-polishing, it is best to simply choose a diamond with optimal polish in the first place. When shopping for an engagement ring or other diamond purchase, be sure to pay close attention to polish ratings and inspect potential diamonds thoroughly before making a decision. With the right attention to detail, you can find a diamond whose exquisite polish will dazzle for years to come.