Pearl Grading Guide

Pearl Grading & Quality Factors – An Insider’s Guide to Grading Pearls

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.

Pearl Value Factors (there’s 7 of them)

Pearl Value Factors - 7 Attributes to Consider

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

Pearl Value Factors - LUSTER

SHAPE - generally the more perfectly round in shape a pearl is, the more rare and prized it is. However many pearl connoisseurs enjoy the unique distinctiveness of baroque pearls.

Baroques are off-round, drop and asymmetrical in shape, and are graded according to symmetry.

Read More: Guide to Pearl Shapes

Pearl Value Factors: SHAPE Round vs Baroque Pearls

COLOR - While many prefer the classic white pearl, pearls come in every color of the rainbow.

Naturally colored pearls like black Tahitian pearls or Golden South Sea pearls are graded on their color’s depth and saturation - the more strongly colored pearls will be more rare and valuable. Certain overtones or exotic body colors command premium pricing at auctions.

Read More: Ultimate Guide to Pearl Colors

Pearl Value Factors: COLOR

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.

Pearl Value Factors: SURFACE QUALITY

SIZE - Large pearls are rare in nature. The majority of cultured pearls harvests consist of pearls under 10.0mm and wild pearls in very large sizes are the rarest of the rare, so the bigger they are the more valuable they are (all other value factors being equal).

Read More: Ultimate Guide to Pearl Sizes 

Pearl Value Factors: Pearl SIZE

NATURAL or CULTURED - 95% of all pearls on the market today are cultured pearls, meaning that humans played a role in pearl formation. Natural, wild pearls from the ocean are very rare and have a premium price.


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.

Pearl Value Factors: PEARL MATCHING

AA+ vs AAA vs AAAA Pearls: What's the Real Difference?

Grading Pearls After Harvest

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.

Explaining Pearl Grading Systems

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. It is known overseas as the Japanese Grading System.

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.

Akoya and Freshwater Pearl Grading

A-AAA Quality Pearl Necklaces Close-Up

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.

A-AAA Akoya Pearl Grades Breakdown

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.

A-AAAA Freshwater Pearl Grades Breakdown


Pure Pearls' Pearl Quality Policy:  I don’t stock any inventory for either Akoya or Freshwater pearls graded under AA+ Quality due to customer satisfaction and quality control issues.

Tahitian and South Sea Pearl Grading

Tahitian Pearl Grading Scales - Close Up of Fine Tahitians

Tahitian and South Sea pearls are primarily graded according to Shape, Surface Quality and Luster.

Variations in pearl body color, overtones and color saturation levels (with as many as 80 “official” variations!) mean that the value factors for Color need to be evaluated individually.

A-D Tahitian and South Sea Pearl Grading Scale Breakdown


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.

So, what’s the deal with AA/AAA type grades?

Pearl Grading: Intermediate AA+/AAA Tahitian Pearl Necklace on Bust

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.

A Note About "Gem" Grade Pearls …

Pearl Grading: What are GEM Grade Cultured Pearls

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.

Common Pearl Blemishes

The inclusions in an Emerald are known in French as “les jardins”, or “the gardens”, and each one is totally unique – a built-in identification system of sorts actually – pearls are just like an Emerald in that respect.

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.

Common Pearl Blemishes Include:


A. Dents/Divots:  Medium to large indentations in the nacre. These can be deep or shallow, match the body color of the pearl, or be a brownish/greyish color.

B. Score Marks:  Scoring is usually light, pencil thin (or slimmer) lines in the nacre. The majority of the time, these marks are colorless and usually not noticeable.

C. Bulleting/Mottling:  A light plating pattern formed on the surface of the pearl while the pearl is formed inside its host oyster. Mottling is not considered an inclusion, as it is actually indicative of thick nacre layers and does not count against the pearls A-AAA grade.

D. Knobs/Tips:  These are growth characteristics, and not necessarily determined to be inclusions. These extrusions form on the end of a baroque-shaped pearl, and can be long or short, bubble-like or pointed. These knobs and tips do not usually affect the durability of the pearl as long as they are not chipped. These features can add touches of unique, artistic flair to a baroque strand of pearls.

E. Pin pricks:  Very small indentations in the nacre. These can be small, individual marks, or grouped together to create a larger area of surface blemishing. Pin prick inclusions do not affect the long-term durability of the pearl, and are colorless or match the pearl’s body color.

F. Circles:  Circling is also another growth characteristic of baroque pearls, with concentric rings running around the circumference of the pearls. They can be very subtle, or grouped together heavily, and impart a one-of-a-kind artistic look to the pearls.

Other pearl inclusions include: wrinkles, blinking, chalky spots, flat spots, ridges and pitting.

Ready to get more in depth about pearl grading by type?

Click the links below to head directly to each pearl type:

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