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Diamond Polish: From Rough Stone to a Beautiful Diamond

Diamond Polish: From Rough Stone to a Beautiful Diamond

When found and excavated deep from the ground, diamonds aren’t the gorgeous stones that you’d find in jewelry stores. Instead, they’re rough stones requiring specific processes to attain sparkly looks.

And one of these processes involves diamond polish. In this article, we’ve covered everything you need to know about diamond polish and what you should consider when purchasing a diamond. So, without further ado, let’s jump right in!

What Is Diamond Polish?

Diamond polish reflects the condition and quality of the facets. If facet surfaces – which, by the way, act like tiny mirrors – are smooth and clear, they’ll reflect light well. However, if these facets aren’t smooth, they can alter light reflection, making the stone appear lifeless and dull.

A rough diamond usually has miniature crystal bumps on the surface. And when the diamond is polished, these tiny bumps are removed. Gemologists achieve higher polish grades by using fine-grain diamond dust on the wheel used for polishing. Diamonds polish diamonds – who would’ve thought!

Diamond Polish Grade

Diamond polish grades are provided based on the smoothness of each and every diamond facet. A diamond expert reviews the stone under magnification to evaluate the quality of the polish.

We recommend diamonds that are given grades of Excellent, Very Good, or Good. Why? 

Stones with polish grades of Fair and Poor won’t reflect light in the same way and will appear dull. Bellow, we’ve covered the GIA polish grades:

  • Excellent: No polish flaws are detectable under 10x magnification (standard loupe used by jewelers).
  • Very Good: Polish flaws are extremely difficult to notice under 10x magnification.
  • Good: Polish flaws are somewhat hard to notice under 10x magnification.
  • Fair: Some polish flaws are noticeable under 10x magnification, and they can, in some cases, be visible to the naked eye. We don’t recommend these diamonds.
  • Poor: Polish flaws are noticeable under magnification and to the naked eye. These diamonds are also not recommended. 

Does Diamond Polish Matter?

Diamond polish impacts a diamond’s beauty, brilliance, and overall appearance – but not as much as you might think. The truth is that hardly anyone can notice the difference between an Excellent and Very Good polish diamond – or even a diamond with a Good polish grade.

Technically speaking, Excellent stones have been polished for a longer period and with a finer diamond dust grain. 

But the fact is, if we can’t tell the difference with magnification, there’s absolutely no way we’ll be able to notice any difference without magnification. So, there’s no real reason to pay additional money for an Excellent polish grade.

While it might look nice on paper to have a pretty word such as “Excellent” written under “Polish” on your diamond certificate, it’s certainly not worth paying extra for it. 

Instead of looking for an Excellent polish grade, it’s way more important to search for a well-cut diamond with plenty of brilliance. Besides reviewing the cut grade, be sure to inspect the stone up close to see how light interacts with it.

Impact Of Polish On Price

A diamond polish grade can affect the stone’s price – but not as considerably as other qualities. Most excellent cut stones also have Excellent polish grades, although some might have a Very Goof – or even Good – polish grade.

A diamond with a lower polish grade can be priced slightly less – which could save you money depending on the diamond’s other qualities.

Most GIA-graded diamonds have an Excellent polish grade, though. In fact, there aren’t many GIA-rated Very Good polish diamonds, so they’re usually more expensive than Excellent polish diamonds.

Since the Excellent polish grade is common in diamonds, a lot of sellers have stones that have been certified by not-so-strict diamond grading labs. They go with a more lenient lab since they don’t want to carry Very Good polish diamonds.

When you shop for diamonds, it’s critical to be on the lookout for a masterfully cut diamond with plenty of brilliance and sparkle. As long as the Polish grade of the stone is Good or better, its beauty won’t be affected by polish flaws – because they won’t be noticeable to the naked eye, anyway. 

So, if you hope to save money, you usually can by going for a slightly lower polish grade.

Related Read: Raw Uncut Diamond Price List: Rough Diamond Prices Guide

Polish Features

The diamond’s polish quality is directly affected by the polishing process. A better polish grade is attained by using a better polishing wheel and by prolonging the process. The naked eye can’t detect most flaws. However, we’ve covered the most common ones below:

  • Abrasion – An area of tiny scratches (or pits) along the edges of facets that produce a fuzzy white line that should otherwise be a sharp facet junction.
  • Burn – Whitish haze, which is a result of excessive heat during the polishing process, or sometimes, the jeweler’s torch. 
  • Laser Manufacturing Remnant – A remnant of laser manufacturing that stays on the polished diamond’s surface and usually appears as a transparent groove.
  • Lizard Skin – An uneven, transparent texture confined to only one facet caused by polishing off-grain.
  • Nick – A tiny notch on a facet junction, typically along the diamond’s girdle or at the culet.
  • Pit – A small opening appearing as a white dot.
  • Rough Girdle – An irregular granular or pitted surface of a bruted diamond’s girdle due to nicks and pits.
  • Scratch – A surface mark, commonly seen as a fine white line that might be straight or curved.
  • Polish Lines – Parallel lines that remain after the polishing process. They can appear white or transparent. A heavy transparent polish line that reaches the surface is, more specifically, called a drag line.

A combination of these polish features affects the gem’s final polish grade. If one of the features is significantly prominent or noticeable, it reduces the overall quality of the diamond.

The Diamond Cutting And Polishing Process

Since diamonds are the hardest material in the world, you can only use a diamond to cut a diamond. Lasers are another alternative – but their utilization is primarily limited to bruting and cleaving purposes.

The tools commonly used in the jeweler’s workshop consist of diamond-bladed edges or discs lined in diamond dust. The process of how diamonds are cut and polished can be divided into five steps:

  1. Planning
  2. Cleaving
  3. Bruting
  4. Polishing 
  5. Inspecting

Step 1: Planing A Rough Diamond

Planning to cut a rough gemstone is one of the most crucial things to get right. While this step can be time-consuming, it’s also the part that determines the final worth of the finished product.

In the planning stages, the diamond cutter will figure out the best shapes of the gem to minimize waste while maximizing the yield of the rough diamond. Usually, the rough gemstone is mapped with a specialized tool that generates accurate measurements.

With this data, a unique program is then used to formulate 3D models of the stone that’ll show the jeweler the best possible ways to optimize the rough diamond.

Related Read: Are Raw Diamonds Worth Anything?

Step 2: Cleaving (Sawing) A Rough Diamond

The cleaving process involves splitting the rough stone into separate pieces. As such, it allows the diamond cutter to work on the pieces separately while utilizing the unpolished gem fully. Mechanical sawing can also be utilized at this stage. In the case of oddly shaped stones, the sawing can be done with cutting tools such as lasers.

Learn More: How Much Does It Cost To Cut A Rough Diamond?

Step 3: Mechanical Bruting 

After the gemstone is split, bruting is performed to make the separated rough diamonds round; this process is also known as girdling. What happens at this stage is that two diamonds are put on a spinning axle across one another. They turn in opposite directions and grind against one another to make a rough girdle finish.

Step 4: Polishing The Diamond Facets

Once the diamond is rounded, the next step is to create and form the diamond’s facets

Here, the diamond cutter paces the rough stone on a rotating arm and utilizes a spinning wheel to polish the gem. That creates reflective and smooth facets on the diamond.

Interestingly, the polishing process is further divided into two steps – blocking and brillianteering.

During blocking, eight crowns, eight pavilion mains, one culet, and one table facet are added to create a single diamond. The importance of this stage is to develop a template for the next step.

The brillianteer will finish the job by adding the rest of the facets and bringing it to a total number of facets. This step holds great responsibility as the diamond’s brilliance and fire are determined at this stage.

Step 5: Inspecting The Polished Diamond

The last step is the inspection process of the gemstone. That’s when the diamond’s checked to ensure it meets the specifications set by the producer. If need be, the stone can be sent back for some touching up – if it doesn’t meet the quality control standards, that is.

Which Is More Important – Polish Or Symmetry?

Diamond symmetry is a bit more critical than diamond polish. The symmetry refers to how well aligned the diamond facets are. For example, do the facet edges on the bottom and top of the stone line up along the girdle? Are the diamond facets aligned symmetrically around the stone?

Symmetry affects how well a diamond interacts with the coming light and how brilliant the stone is. A diamond with proper symmetry allows light to traverse through the stone as it should. The light bounces off the angles and facets, back through the table, and to the viewer’s eyes.

And a diamond with poor symmetry? It will send light through at defective angles, which might exit at the bottom of the stone. When light doesn’t reflect back to the viewer’s eyes, it appears lifeless and dull. That’s the reason why symmetry is crucial to the diamond’s beauty.

The symmetry grade is based on the presence and visibility of deviations at 10x magnifications. Several factors come into play when a stone is graded for symmetry, and these include missing facets, extra facets, misalignment, and off-center table.

Here, we’ve covered a breakdown of each symmetry grade:

  • Excellent – Diamonds with this grade have very few (if any) deviations. Their tables are adequately centered and don’t miss any facets or have any extra facets.
  • Very Good – These diamonds have a few slight deviations, and there might be some slight misalignment.
  • Good – Diamonds with this grade have few deviations. Diamond’s brilliance might be affected by factors such as missing facet or pavilion angle variation.
  • Fair – These stones have several deviations. The stone’s brilliance is lowered due to the misalignments and misshapen features.
  • Poor – Diamonds with Poor symmetry have several apparent deviations, and a diamond’s brilliance is significantly lowered. They could have a combination of missing facets, off-center table, and misshapen facets.

In general, though, it’s impossible to differentiate between a diamond with “Excellent” and “Very Good” symmetry – just like it’s impossible to notice the difference between “Excellent” and “Very Good” polish.

Your diamond won’t be affected negatively by symmetry or polish as long as you opt for a stone with a Good (or better) polish grade and a Good (or better) symmetry grade.

Related Read: How Do I Get My Rough Diamond Certified?

Bottom Line

One of the key components in the diamond manufacturing process is diamond polish. It’s the condition – and the quality – of the facet surfaces. Diamond polish plays a role in the diamond’s light performance – although it’s impossible to tell the difference between Excellent and Very Good polish grades. 

Our advice? Regardless of what the certificate might say, always inspect the gem up close and observe how light interacts with its surface.