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Summary graphic of pearl grading: seller AAA letter scales with no single standard, GIA’s seven value factors, and French Polynesia’s Top Gem to D categories for Tahitian pearls

Pearl Grading Explained: AAA Letters, GIA’s 7 Factors and Tahiti’s A-D

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There is no single, universal pearl grading scale. The A, AA and AAA letters on a listing are the seller’s own scale, GIA describes a pearl through seven separate value factors instead of one grade, and French Polynesia sorts Tahitian pearls into its own lettered categories. To compare pearls from different sellers, look past the letter to what sits behind it: a factor-by-factor description, or a lab report that says whether the pearl is natural or cultured.

As of October 10, 2026: GIA classifies pearls by size, shape, color, luster, surface, nacre and matching, and in 2025 replaced its pass-or-fail nacre grade with a five-step scale from Excellent to Poor. Since 2023 GIA has added a Hanadama comment to classification reports for akoya pearls that meet a defined range. French Polynesia’s marine resources agency lists five surface categories for Tahitian pearls, from Top Gem down to D. In the US, the FTC’s Jewelry Guides require cultured or imitation in front of the word pearl whenever the pearl is not natural.

Why pearl grading has no single universal scale

Diamond shoppers get a fixed vocabulary from the grading labs, the kind laid out in our diamond clarity chart. Pearls never settled on one. Writing in GIA’s journal Gems & Gemology in 2021, two GIA pearl gemologists put it this way: “The competing, often company-specific methods and coded terminology made the systems difficult to understand and employ consistently.” They added that “Agreeing on a universal approach to classify pearls has remained one of the main challenges facing the pearl industry.”

A buyer usually meets four systems: seller letter grades, GIA’s seven value factors, French Polynesia’s categories for Tahitian pearls and the Japanese term hanadama for top akoya. They weigh much the same things but draw the lines in different places. Our pearl buying guide covers pearl types and how nacre forms; this page sticks to the grading systems.

What A, AA and AAA mean on a pearl listing

The A-to-AAA scale, often stretched with AA+, AAA+ or AAAA, is the one most shoppers see first, and nobody owns it. Even a retailer that publishes its own table says so. Pearl Paradise writes that “A, AA, AA+, AAA and AAAA are not governed by a single universally adopted scale,” and introduces its chart with: “These are the standards we apply within the range we buy in. They are ours, not an industry standard, and we publish them so you can hold us to them.”

Here is how that one seller fills in the letters for akoya, as its page read on October 10, 2026. Its AAA calls for a surface that is 95% clean or better, AA+ for 85–95% clean and A for 75–85% clean. Its luster wording runs from bright and sharp at AAA to bright but hazy-edged at A. Another shop can set its cutoffs higher or lower and still print AAA, so the letters only compare pearls within one seller’s stock.

So ask what the letter means on the piece in front of you: how sharp the luster is, how much of the surface is marked, how round the pearls are, how well they match and how the nacre looks. An answer given factor by factor can be compared with another seller’s. A bare AAA cannot.

GIA’s 7 pearl value factors

GIA’s approach goes back to 1967, when Richard T. Liddicoat Jr. proposed describing pearls through seven value factors. GIA’s consumer page lists the qualities that set value as “size, shape, color, luster, surface quality, nacre quality, and—for jewelry with two or more pearls—matching.” There is no overall grade. Each factor gets its own description, reached by comparing the pearl with a set of master pearls.

Factor What GIA looks at GIA’s terms
Size Diameter in millimeters Measured, not graded
Shape Outline of the pearl Seven shapes, round to baroque
Color Bodycolor, overtone, orient Described by hue and tone
Luster Sharpness of reflections Excellent to Poor
Surface Blemishes by size, number, place Clean to Heavily Spotted
Nacre Smoothness and continuity Excellent to Poor (since 2025)
Matching How alike the pearls are Excellent to Poor, or Not Applicable

GIA singles out luster: “Of the seven pearl value factors, luster might be the most important.” At the top of its luster scale, reflections look bright and sharp; at the bottom, they look dim and diffused. GIA judges luster against each pearl variety’s own standard.

Surface is judged on the size, number, location and visibility of blemishes, and heavy marking is more than cosmetic: GIA says numerous or severe surface characteristics can affect a pearl’s durability. Among the shapes, GIA calls round the hardest to culture and the rarest. Matching applies only when a piece holds two or more pearls.

One limit is easy to miss. GIA’s 2021 description says the system applies to nacreous pearls “and exclusively for the three dominant types of saltwater cultured pearls: akoya, South Sea, and Tahitian.” Freshwater pearls can still get a GIA identification report, with luster, surface and matching on the combined report, but the full seven-factor report is built for those three.

Nacre: thickness and quality are not the same thing

Nacre is the material a pearl is built from, layer after layer; in a bead-nucleated pearl it grows over a shell bead. CIBJO, the World Jewellery Confederation, defines nacre thickness as the coating over the bead, “usually expressed as an average in millimetres,” and states that “Nacre thickness is only relevant in the case of beaded cultured pearls.” Its Pearl Book also warns that thickness “may not be correlated with nacre quality,” so a thick coat can still be a poor one.

GIA reworked its nacre factor in 2025. Before that, nacre was simply Acceptable or Unacceptable. The new scale has five ranges, Excellent, Very Good, Good, Fair and Poor, set by how smooth and unbroken the nacre looks on and just below the surface, judged without magnification. GIA’s researchers wrote that “most cultured pearls of commercial grade fall into the Good nacre quality range,” and that “each cultured pearl type has a minimum parameter for nacre thickness.” GIA did not publish those minimums.

A thickness figure appears on a GIA report only on request: GIA says nacre thickness measurements “are provided as optional descriptions on GIA pearl reports,” though reports will flag nacre that is too thin or damaged. A 2025 study from GIA’s Bangkok laboratory cites “the typical nacre range of 0.15 to 0.50 mm in traditional akoya pearls.” GIA credits part of South Sea pearls’ value to thick nacre built up over a long growth period. Pearls grown from implanted mantle tissue alone, a method GIA also describes, have no bead to measure over.

GIA’s quick check works at any counter: if the bead shows through, or the pearl looks dull and chalky, assume the nacre is thin.

Tahitian pearls: Top Gem, then A to D

Tahitian cultured pearls are the one type whose classification a government spells out. French Polynesia’s Direction des Ressources Marines (DRM), the agency that oversees pearl farming, says surface quality is judged with the naked eye and lists five categories:

Category DRM description (our translation)
Top Gem Perfect quality, no defects
A Tiny defects, hard to see
B Slight imperfections
C Imperfections on less than 2/3 of the surface
D Fairly significant irregularities

The same page puts typical Tahitian pearls at 8 to 14 mm and tells buyers to ask their jeweler for a certificate of authenticity covering origin and quality. Notice what these categories measure: surface. Color, luster and shape are described separately, so a Tahitian strand sold as AAA carries a seller’s letter, not one of the DRM’s categories.

What happened to the 0.8 mm nacre rule

Older guides say every exported Tahitian pearl had at least 0.8 mm of nacre, and for years that was the rule. A 2016 study by Ifremer, the French marine research institute, published in the Journal of Shellfish Research, describes the regime of the time: government rules required exported pearls to be X-rayed to confirm nacre of at least 0.8 mm, thinner pearls were rejected, and the grades ran A, B, C and D plus R, a reject class barred from export.

In July 2017 French Polynesia adopted a new pearl law, which the DRM describes as a rebuild of the sector’s rules around new governance bodies. Gemologist Renée Newman, writing in the trade magazine Jewellery Business in 2025, says the government “used to impose a minimum nacre thickness on all exported pearls of 0.8 mm” and that “that requirement was dropped in 2017.” We could not open the law itself on French Polynesia’s legal database when we checked, so treat a 0.8 mm promise on a Tahitian listing as the seller’s own claim and ask for the measurement in writing.

Hanadama and the akoya top tier

Hanadama is a Japanese trade term for the best white akoya. GIA says it studied how the word is used and pinned down the quality range “commonly agreed upon within the pearl trade.” Since 2023, GIA adds a Hanadama comment to its classification reports when akoya pearls meet all of these: “Round to near-round shape, white body-color (with or without overtone), excellent luster, clean to lightly spotted surface, excellent to very good matching, and sufficient nacre thickness and quality.” GIA said the comment carries no extra fee.

The comment applies to akoya only. If a strand comes with a hanadama certificate from a laboratory other than GIA, ask which lab issued it and what it measured; the word on the paper is only as useful as the criteria behind it.

What the FTC rules say about pearl names

US law does not set pearl grades, but it does regulate the words. The FTC’s Jewelry Guides (16 CFR Part 23) reserve the plain word pearl for one formed without any human help, and define a cultured pearl as nacre grown by a mollusk over a nucleus that people planted. GIA says it helped revise them. Under the guides:

  • A cultured pearl may not be called simply a pearl. The word must be preceded, just as prominently, by cultured or cultivated.
  • An imitation must carry artificial, imitation or simulated in front of pearl, and labels such as faux pearl or fashion pearl do not get around that.
  • Natural, and look-alike spellings such as natura, may not describe a cultured or imitation pearl.
  • Sellers may not misstate how a cultured pearl was grown, the size of its nucleus, how long it stayed in the mollusk or how thick its nacre is.
  • Treatments must be disclosed when they are not permanent, create special care needs or significantly affect value.

None of this grades a pearl. It does mean a stated nacre thickness is a claim the seller must stand behind, and a US listing that says pearl with no qualifier is claiming a natural pearl. CIBJO’s Pearl Book sets the same expectation internationally: full disclosure of material information whether or not the buyer asks.

What to ask a seller for before you pay

Because letters do not travel between sellers, the paperwork matters more than the grade. GIA’s laboratory issues three pearl reports, and they answer different questions:

GIA report What it covers
Pearl Identification Natural or cultured, treatments, mollusk, water type, size, shape, color
Identification & Classification All of that, plus luster, surface and matching
Cultured Pearl Classification All seven value factors; type is declared by the submitter

GIA says the Identification Report “confirms that the pearl(s) is/are natural or cultured, not a simulant or imitation, and describes any detectable treatments.” The Cultured Pearl Classification Report starts from the owner’s word: “Upon submission, clients must identify their pearls as untreated and cultured, and by pearl type,” and GIA then runs only limited testing to confirm the stated mollusk and color origin. If a listing claims natural pearls, the identification report is the one to ask for.

Before paying, ask for:

  • The report and its number, so you can check it with the lab yourself (see our post on what to do when a certificate number does not match the listing).
  • Natural or cultured, stated in writing, along with any treatment.
  • Nacre thickness in millimeters for bead-nucleated pearls, an optional extra on a GIA report.
  • For Tahitian pearls, the DRM category if the seller uses one, plus the certificate of authenticity the DRM tells buyers to request.
  • For a strand or pair, the matching description, because one excellent pearl does not make an excellent necklace.

A listing that says GIA tested but shows no report number deserves the scrutiny we describe in our post on GIA-tested claims on gemstone jewelry. A lab report and an appraisal do different jobs; our guide to jewelry appraisals explains when you need the second.

A grade also describes a pearl only on the day it was examined, not after years of wear. The DRM names chlorinated water, perfume and hairspray as a pearl’s main enemies. Storage matters too, which is the problem behind our fix for a pearl necklace that feels sticky after storage.

Frequently Asked Questions

What is the highest pearl grade?

There is no single highest grade, because each system tops out differently. On a seller’s own letter scale the letters climb from A to AAA, and some sellers add AAAA or a named tier above that. GIA describes each value factor separately rather than giving one overall grade, adds a Hanadama comment for akoya pearls that meet its defined range, and French Polynesia’s top Tahitian category is Top Gem.

Is AAA a good grade for pearls?

AAA is usually near the top of the seller’s own scale, but no organization defines or polices it, so one shop’s AAA can be another shop’s AA. Ask the seller what AAA means for luster, surface, shape, matching and nacre on that piece, and compare those descriptions rather than the letters.

What does GIA grade on a pearl?

GIA describes seven value factors rather than giving one grade. Size is measured in millimeters, shape and color are described, luster, nacre and matching each run from Excellent to Poor, and surface runs from Clean to Heavily Spotted. Matching is listed as Not Applicable for a single pearl.

What do the A, B, C and D grades mean on Tahitian pearls?

French Polynesia’s Direction des Ressources Marines describes them as surface categories judged by eye. Top Gem has no defects, A has tiny defects that are hard to see, B has slight imperfections, C has imperfections on less than two thirds of the surface, and D has fairly significant irregularities.

How thick should the nacre on a pearl be?

It depends on the type. GIA describes 0.15 to 0.50 mm as the typical nacre range for traditional akoya pearls, and says each cultured pearl type has its own minimum. The old 0.8 mm export minimum for Tahitian pearls was dropped in 2017, according to gemologist Renée Newman, so ask for a measured figure in writing instead of assuming one.

How can I tell if a pearl is natural or cultured?

The reliable answer comes from a lab. GIA gemologists use standard and advanced testing to identify the pearl type, and a GIA Pearl Identification Report states whether a pearl is natural or cultured and notes detectable treatments. Under the FTC Jewelry Guides, a cultured pearl must be labeled cultured or cultivated, and the word natural may not be used for a cultured or imitation pearl.

What is a Hanadama pearl?

Hanadama is a Japanese trade term for a top range of white akoya pearls. Since 2023 GIA adds a Hanadama comment to its classification reports when akoya pearls are round to near-round and white, with excellent luster, a surface rated clean or lightly spotted, matching of very good or better, and enough nacre of sound quality.

Sources

Grading standards, fees and policies are quoted from each organization’s own pages on the date shown and change often, so check the current terms before you submit, buy or sell. This article is general information, not investment, tax or legal advice. Top Tier Drip is not affiliated with any grading service, laboratory, mint or dealer named here and earns nothing from them.

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