Pearl Grading Guide (2024)

Nacre thickness is possibly the most important Value Factor for pearls, as it is the foundation upon which all other characteristics rest.A pearl without thick, well-layered nacre will not look as beautiful as other pearls and will not last as long over the years.

Pearl types such as Tahitians and South Sea pearls have extremely thick nacre, often averaging between 2-4mm thick around the bead nucleus inside.

Hanadama Akoya pearls from Japan also have minimum nacre thickness requirements in order to qualify for the coveted PSL Certificate. X-rayed pearls must have at least 0.4mm thickness, and often have deeper thicknesses than that.

More than any other Value Factor, Luster is by far the most important. A pearl without good luster is really just a chalky bead. Luster is best described as the glow that comes from within the pearl, which is produced by light entering the pearl and reflecting back at the viewer through the layers of nacre. The quality of the pearl's luster is directly related to how even and smooth the layers of nacre are.

Luster measures how bright and shiny a pearl appears. Jewelers also use the term luster to measure the sharpness of objects reflected on the pearl’s surface.

This can be quantified by how detailed that reflection is (i.e. you can see your entire face), or how sharp and defined reflected light sources appear on their edges. The sharper the edges of reflected light sources the better the luster is.

The next most important Value Factor, surface quality measures how clean, smooth and free from blemishes a pearl appears. Most all pearl buyers will notice a degree of surface imperfections. The key factors to surface quality imperfections are how noticeable they are and if they seriously affect the durability of the pearl.

Blemishes (also called inclusions) can be:

• Abrasions- scratches or scuffs that affect the luster or color of the pearl.
• Spots- minor color variations.
• Bumps- tiny bubbles on the surface of the pearl
• Wrinkles- where the nacre isn't smooth.

Serious surface quality issues are usually chips and gaps, which will lower the value of even the most lustrous pearls. Why? These particular imperfections can cause the pearl to crack or peel. Some surface characteristics are hardly noticeable, even to a pearl expert. A good example would be a minor flaw near the hole drilled in the pearl.

All other factors being equal, the bigger the pearls are the better. Cultured pearls can range in size from tiny 1.0mm seed pearls up to 21.0mm and rarely, even larger. To date, the largest cultured pearl in the world is an astonishing 29.65mm South Sea baroque.

Like diamonds, size can contribute to exponentially increasing prices with each millimeter size up. This is because larger pearls are much harder to cultivate, take much longer to produce and thus are much rarer.

Perfectly round pearls are the “gold standard” when it comes to cultured pearl jewelry. These are the most conventional of all pearl shapes, and what almost every pearl shopper thinks of when they think of a classic pearl necklace.

After perfectly round pearls, the next most popular shapes are smooth Drops, then Buttons and finally Baroques.

The most important consideration is that the pearl features evenly symmetrical shapes, which are most pleasing to the eye and more easily used in most pearl jewelry styles.

This Value Factor looks at the strength of the pearl’s body colors and overtones. The more easily visible and saturated, the better. Certain overtones are rarer and thus more valuable than others, and will increase the pearl’s price.

For example, 22K Golden South Sea pearls are worth much more than Golden pearls with a 14K color. White South Sea pearls with a fine rose overtone are rarer than pearls with silver, and that will contribute to a higher price tag (all other factors being equal).

Matching measures how beautifully pearl necklaces, earrings, bracelets and sets are matched. Pearl matching should take into account:

• • Size
  • Shape
  • Surface Quality
  • Luster
  • Body Color
  • Overtone

Multi-colored strands should be matched according to all these factors, but Body Color and Overtones can be mixed. As long as the strand has a pretty overall tone and aesthetic, the mixed colors do not count negatively against the pearl’s overall grade.

• Surface Quality is 95% Clean or better.
• Luster is Very High to Excellent: Reflections on pearl surface should be Easily Recognizable.
• Pearl Earrings are clean on front and sides.
• Pearl Necklaces and Bracelets will be blemish-free for casual observers. Some tiny inclusions allowable, but nothing major.
• Akoya pearls should feature Excellent matching for necklaces and bracelets. There should be virtually no difference between each pearl in a necklace, bracelet or matched set.
• Freshwater pearl necklaces, bracelets and matched sets will have very little differences for matching for shape, size and surface quality.

• Surface Quality is 90-95% Clean or better.
• Akoya pearls feature thick nacre measuring 0.4mm or more. Freshwater pearls are solid nacre.
• Luster is Very Sharp to High: Reflections on pearl surface should be Very Good, mostly distinguishable with some slight blurring.
• Earrings are clean on fronts. One to two small inclusions allowable on sides or backs.
• Pearl Necklaces and Bracelets will be mostly blemish-free for casual observers.
• Akoya pearls should feature Excellent to Very, Very Good matching for necklaces and bracelets. There should be little to no difference between each pearl in a necklace, bracelet or matched set.
• Freshwater pearl necklaces, bracelets and matched sets may feature some differences in matching for shape, size and surface quality.

• Surface Quality is 75-80% Clean or better.
• Nacre is solid for Freshwater pearls. May be thin in places for Akoya pearls.
• Luster is Good to High: Reflections on pearl surface will be blurry.
• Earrings are not clean on fronts.
• Pearl Necklaces and Bracelets will feature multiple blemishes, and some deeper inclusions.
• Akoya pearls should feature Very Good matching for necklaces and bracelets.
• Freshwater pearl necklaces, bracelets and matched sets will feature differences in matching for shape, size and surface quality.

• Nacre is visibly thin for Akoya pearls and nucleus will be visible under certain lighting conditions. Freshwater pearls are solid nacre.
• Luster is Fair to Good for Akoya and Freshwater pearls. You should be able to see your face’s outline, but not any fine details.
• Light sources reflected on pearl surfaces will be blurred with fuzzy edges.
• Blemish free 60% of all pearl surfaces.
• Pearl earrings will have marks on the front.
• Necklaces will have blemishes easily visible to the casual observer with multiple deep inclusions visible.
• Decent pearl matching; for Freshwater and Akoya pearls some variation in color, tone, luster, shape or size may occur.

Extremely thick nacre. For Tahitian pearls, nacre depth is a minimum of 0.8mm. White and Golden South Sea pearls average 2-4mm nacre thickness. Freshwater pearls are solid nacre.

Surface Quality is 90-95% clean of blemishes or better

Earrings, Pendants and Rings will set clean on front and sides. One small inclusion allowable on back.

For Tahitian and South Sea pearls, necklaces will present as mostly clean, with a few small, shallow blemishes allowable with up-close scrutiny. Freshwater pearl strands will be 95-99% clean to the eye. No deep inclusions allowed.

Luster will be Very High to Excellent. Reflections in the surfaces highly detailed, but some blurring is allowable.

Extremely thick nacre. For Tahitian pearls, nacre depth is a minimum of 0.8mm. White and Golden South Sea pearls average 2-4mm nacre thickness. Freshwater pearls are solid nacre.

Surface Quality is 80-90% clean of blemishes or better.

Earrings, Pendants and Rings will set clean on front. Small, shallow inclusions allowable on sides, and one or two inclusions allowable on back.

Necklaces will present as mostly clean, with small, shallow blemishes allowable throughout the strand. Up to 2 deep inclusions allowed.

Luster will be Very High. Reflections in the surfaces mostly detailed, but blurry.

Extremely thick nacre. For Tahitian pearls, nacre depth is a minimum of 0.8mm. White and Golden South Sea pearls average 2-4mm nacre thickness. Freshwater pearls are solid nacre.

Surface Quality is 70% clean of blemishes or better

Earrings, Pendants and Rings will not set clean on front. Moderate inclusions allowable on front and sides, deeper inclusions allowable on sides and back.

Necklaces will present as spotted, with combination of small and medium-sized blemishes allowable throughout the strand. Up to 4-5 deep inclusions allowed.

Luster will be Good to High. Reflections are blurry.

Extremely thick nacre. For Tahitian pearls, nacre depth is a minimum of 0.8mm. White and Golden South Sea pearls average 2-4mm nacre thickness. Freshwater pearls are solid nacre.

Surface Quality is 50% clean of blemishes.

Earrings, Pendants and Rings will not set clean on front. Moderate inclusions allowable on front and sides, deeper inclusions allowable on sides and back.

Necklaces will present as spotted, with combination of small and medium-sized blemishes allowable throughout the strand. Up to 8 deep inclusions allowed.

Luster will be Good to Poor. Reflections are very blurry.

*Pearls of Joy does not offer AA or A Quality Freshwater, Tahitian or South Sea pearls.

• Minimum certified nacre thickness of 0.4mm or better.
• Surface Quality is 95% Clean or better.
• Visible "Aurora" (orient) effect.
• Luster is Very High to Excellent: Reflections on pearl surface should be Easily Recognizable.
• Hanadama Pearl Earrings are clean on front and sides.
• Hanadama Pearl Necklaces and Bracelets will be blemish-free for casual observers. Some tiny inclusions allowable, no major blemishes.
• Hanadama Akoya pearls should feature Excellent matching for necklaces and bracelets. There should be virtually no difference between each pearl in a necklace, bracelet or matched set.

• Solid nacre.
• Pearl shape is near-perfect round, with less than 3% variance from perfect rounds.
• Surface Quality is 95% Clean or better.
• Luster is Very High to Excellent: Reflections on pearl surface should be Easily Recognizable.
• Pearl Earrings are clean on front and sides.
• Pearl Necklaces and Bracelets will be blemish-free for casual observers. Some tiny inclusions allowable, but nothing major.
• AAAA Grade Freshwater pearl necklaces, bracelets and matched sets will have little to no differences for matching for shape, size and surface quality.