Pearl Grading: All About the A-AAA Pearl Grading Scales (2024)

Wanna know a secret?

Pearl grading standards are a MESS. Seriously – standards are all over the place, they vary from seller to seller, farmer to farmer and auction to auction. Walking an industry show and talking to pearl farmers entails learning as many as 30 new grading scales in day in order to navigate the pearls on offer.

What I take with me when I go is my special grading hank that features pearls with all my grading benchmarks so I can compare pearls to make sense of it all while I’m there.

Now, obviously you don’t have that option.

BUT, what I can do is create simple breakdown of each grade’s specific standards using the A-AAA and A-AAAA Grading Scales so you know exactly what to look for when purchasing a pearl necklace or earrings, bracelet, pendant, etc.

Follow the links below to jump straight to the specific pearl grading guide you’re looking for, or read on a bit more for an overview of the popular Grading Scales in use today, and how they relate to your pearls.

LUSTER - this is the biggest value factor to pay attention to.

Luster measures the rate of reflection (how crisp and detailed it is) on a pearl’s surface, and the amount of light reflected on the pearls.

Beautiful luster makes or breaks pearls as a gemstone - pearls without great luster can end up looking like chalky beads. Basically, the brighter, sharper and more reflective a pearl is, the more valuable it will be.

Read More: What Causes Luster in a Pearl

SURFACE BLEMISHING - Pearls that feature clean surfaces without inclusions like pin-pricks, scoring marks, chalky spots and wrinkles will be much more highly valued than pearls with multiple blemishes.

Because pearls are a product of nature however, there will always be some form of blemish - even if you can’t view them with the naked eye. This is why we will never call our pearls flawless.

MATCHING -describes how well pearls are matched within a pair, or an entire layout.

For Akoya pearls, matching must be near-perfect with little to no variation from pearl to pearl throughout the entire Akoya strand. Matched pairs for Akoya earrings must feature less than 0.15mm difference – the match must be as close to exact as humanly possible.

For South Sea and Tahitian matched pairs for earrings, a difference of up to 0.50mm is allowable between pearls. Tahitian and South Sea pearl necklaces will often feature graduated layouts (meaning pearls can range in size by a few millimeters), and multi-colored layouts are common.

Right now, there’s no set internationally agreed upon grading scale for pearls. That means that pearl grading is subjective, depending on the seller you’re dealing with.

My biggest concern regarding A-AAA and A-AAAA vs 6A or AAAAA+ grading scales is that instead of making pearl grading standards as easy as possible to understand, it actually creates a ton of confusion. So be careful! If you see a strange grade like AAAA++, then buyer beware.

Here’s how that works: Instead of having AAA/AAAA representing the "best" pearl grades, the quintuple AAAAA is used to represent AAAA grade pearls, and the AAA actually represents the AA+ grade, with subsequent downgrades in pearl quality all the way down the line.

So you think you're buying the best quality pearls at a lesser price than you'd pay here, but you're actually only getting AA+ Quality pearls, and shelling out a premium for pearls that display those "higher" grades. Often this inflation of the grading scale isn't properly described, and many customers new to pearls and unfamiliar with the intricacies of pearl grading end up disappointed.

Pro-Tip: Ask to see a detailed description with specific criteria for each pearl grade so you know exactly where you stand. It’s easier to compare apples to apples that way.

PurePearls.com uses both the A-AAA and A-AAAA grading scale, and what I like so much about them both are their simplicity. Grades are based upon a certain percentage of surface blemishes allowable, specific rate of luster (the sharpness of reflections) and shape.

The A-AAA scale is used most commonly with Akoya pearls.

Our Freshwater, Tahitian and South Sea grading scales of A-AAAA are converted from the 4-tier systems that most pearl farmers use. Pure converts all A-D Tahitian and South Sea pearl grades to the A-AAAA scale to make things easier to understand and consistent across the board.

Cultured Akoya pearls are graded using the Japanese Pearl Grading System, using the A-AAA Scale with the addition of Hanadama Akoya pearls representing the highest pinnacle of the pearl type.

The A-AAA system evaluates pearls according to Surface Quality, Luster, and perfection of Shape (roundness and symmetry). Akoya pearls are also graded on Nacre Thickness, which is a visual inspection completed by the grader rather than via x-ray analysis. The only exception to this is for Hanadama pearls which are x-rayed at the Pearl Science Laboratory in Tokyo.

Cultured Freshwater pearls are graded using a version of the Chinese Pearl Grading System which separates pearls into Class I, Class II, Class III and Class IV grades according to Surface Quality, Luster, Matching and perfection of Shape (roundness and symmetry).

In order to simplify this classification system and maintain consistency with other popular grading systems, many vendors convert this Class system to a whole letter A-AAAA Scale. Class I pearls would be the highest grade, with Class IV representing the lowest pearl grades. Much of the Chinese Grading System utilizes the Japanese A-AAA Grading System to evaluate pearls (Luster and Surface Quality mainly), and ditches the "+" signs, relying on whole-letter grades instead.

See the chart below for a detailed breakdown of theA-AAAA system and the statistical benchmarks pearls need to meet in order to make the grade.

Pro-Tip: Tahitian cultured pearls MUST have a minimum nacre depth of 0.8mm per side (so 0.16mm total) in order to qualify for export. Harvests are examined and certified at random by the Perliculture Department of the Pearl Ministry for nacre thickness. Average nacre thickness for Tahitian pearls remains at 1.0mm depth or more.

Pure Pearls' Pearl Quality Policy: To maintain a high level of quality for all my customers, I only stock AAA Quality Tahitian and South Sea pearl pendants, earrings and rings. This means that all our Tahitian and South Sea pearl jewelry will set clean with the brightest luster and prettiest overtones.

With full strand pearl grading, there will be layouts that combine many AAA Quality and AA Quality, or AAA and AAAA Quality pearls. This is done to maintain a consistent “tone” throughout the necklace in terms of matching for size, overtone or luster, and also to ensure price points remain reasonable.

These strands would be graded as AA/AAA or A/AA or AA/A and so on. Essentially, what this means is that a layout could have a AA Quality rate for Surface Blemishing, but fantastic AAA Quality Luster (or vice-versa, with very clean pearls and medium-grade luster), and so receive a AA/AAA Quality grade.

It is true that with pearls and other precious colored gemstones that there will always be a better "best of the best" specimen than what fits in the A-AAAA Scale … pearls that cannot be sold at a "lot price". This is not to be confused with ‘AAAA’ pearls!

Gem Quality pearls are rare strands or pearls come along once in a while with unparalleled luster, nacre thickness, crystalline transparency, orient, etc., and simply must stand on their own and be priced out individually based upon what the market will bear.

I always keep a special eye out for rare and beautiful pearls on buying trips each year, and regularly send out special email updates for collectors about the newest treasures I come across. These items are not typically offered on the site as a standard item to be ordered due to rarity and pricing issues (and they move fast!).

Feel free to contact me directly if you’re looking for one of a kind, rare items at: sales@purepearls.com or sign up for the Collector’s Email List.

Pearls are what’s known as ‘organic gemstones’. They are the creations from a biological process (the others being coral, amber, jet and ivory), and as such will feature growth characteristics … kind of like Mother Nature’s fingerprints on her creations.

In this section we’re going to learn how to tell what a blemish is, and what it is not. The slightly circled Tahitians pictured above are a perfect example to work with as they feature a good variety of common inclusions, as well as typical growth features that aren’t considered inclusions at all.