How Pearls are Graded

If you love the intricate beauty of pearls, then you have come to the right place. Our goal with this blog is to help educate people on what distinguishes one pearl from another as well as develop a deeper appreciation for these exquisite gems of the sea.

For starters, there are two main classes of pearls – saltwater and freshwater pearls. The majority of freshwater pearls are farmed in China. Saltwater pearls are known for their high luster. In contrast to oysters that Saltwater pearls come from, Freshwater pearls come from mussels. Universally, saltwater pearls are considered to be of very high value. In a future blog, we will spend more time outlining the vast difference in quality between salt and freshwater pearls. For the most part, the overwhelming majority of this blog will be solely dedicated to the discussion of saltwater pearls.

Pearls are graded in a very similar fashion to diamonds. Pearls however have their own grading scale. At Seven Seas Pearls, there is always a certified GIA (Gemological Institute of America) Pearl Graduate on site so you can be sure you are getting the exact quality you are paying for. For the time being, there are two systems of grading that are commonly used: the AAA – A system and the A-D system. The AAA – A system is the most popular system of grading in the United States and is also the system that Seven Seas Pearls uses to grade pearls.  While this is the system we use, we also take our grading one step further (we will explain more about that in a bit). Because the AAA -A grading system is the most popular and also the system we use, we will explore how pearls are graded according to this system in this blog.

Many people are very familiar with the diamond grading scale. The two most important criteria for diamonds to be graded on are the color and clarity. If you have ever spent time looking at diamonds, you know that it is very important to have a balance of these two factors. A diamond that has brilliant color can appear lifeless and dull if the clarity is poor. Adversely, if a diamond has perfect clarity and the color is off, again the diamond would be less than desirable.

Typically pearls are graded as a whole piece – this is very different from diamonds. Diamonds are graded individually on cut, color, clarity and carat. At Seven Seas Pearls, we feel that it is important to grade each pearl individually on their luster, surface clarity and nacre. At Seven Seas Pearls, when a pearl is graded in each of these categories, the overall grade is averaged out to be the official grade of the pearl. Very similar to diamonds, if a pearl has excellent luster and nacre, but the surface clarity is not desirable, then you are left with a pearl necklace that while lustrous, has many demarcations.

At Seven Seas Pearls we believe that there is a flaw in the traditional AAA-A grading system. The grading system as it currently exists, does not allow for pearls that are flawless, have perfect luster or top nacre. As a result, we have added an additional category that describes pearls that have a 99.99% clean surface; we label these pearls as “AAA Flawless”. As we mentioned, we grade each pearl individually on their surface clarity, luster and nacre. While the traditional grading system averages out all aspects for an overall grade, we feel that this does not accurately represent the value of the pearl. Therefore, in terms of luster, we have added another category: AAA Gem – a pearl that is rated with AAA Gem by Seven Seas Pearls will have the best possible luster for that type of pearl.  The nacre is also a very important aspect of determining the overall pearl grade. At Seven Seas Pearls, we have five categories for determining the quality of nacre: Top, Very Thick, Thick, Medium and Thin. Below is a chart that will give an excellent visual explanation for how we grade our pearls at Seven Seas Pearls.


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At Seven Seas Pearls, we feel that pearl education should consist of at least three important but separate criteria 1.) Pearl origin and the difference between salt and freshwater pearls 2.) The clarity of the pearl surface and 3.) The luster and nacre of a pearl.

Now that we have introduced you to how pearls are graded, we invite you to see and examine the difference for yourselves in these images. The first image is an excellent example of how important surface clarity is. Can you see the difference between these two pearls? One is smooth and clean and the other has many demarcations.


This is an excellent example of luster. One pearl has excellent luster – the other is very poor. Luster refers to the shine of the pearl. Many people feel that the luster is the most important aspect to look for in a pearl – but while a pearl may have excellent luster, if the nacre is thin – the luster won’t last long.

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In a future blog we will discuss more in detail the importance of nacre – but these two images are an excellent visual example of why nacre is so important.

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In our next blog we will go more in depth as to how our grading system and the standard grading system of pearls works. Check back soon for our next blog!


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