PEARL GRADING SYSYTEM
Unlike other gemstones grading, there is no standardised grading system in the pearl industry. Every company has its own grading system that is subjective and unique. While there are many systems in use, most reputable pearl sellers use either the AAA-A or A-D quality classifications.
Understand The Pearl Grading Scale
In general, the AAA -A and A-D scales are interchangeable for all pearl types. The AAA -A scale includes AAA, AA +, AA and A, with AAA representing the highest grade and A the lowest grade. In A-D scale, A represents the highest grade, followed by B, C and D.
| Grade | AAA-A | A-D |
|---|---|---|
| Very High | AAA | A |
| High | AA+ | B |
| Medium | AA | C |
| Low | A | D |
However, the result will vary from one company to another as there is no universal standard. For example, a high quality pearl was rated AA + by one company, while a pearl with lower lustre was given a higher grade of AAA by another.
The AAA-A scale is primarily used for grading Akoya and freshwater pearls, but it is also being applied to South Sea and Tahitian pearls by some sellers. The A-D scale, also known as the "Tahitian System" in French Polynesia, is exclusively used for grading Tahitian and South Sea pearls. This scale is the standard in producing countries, but some sellers still prefer to use the AAA-A scale for these types of pearls.
Pearl Grading Charts
To provide a clearer understanding, below are grading charts for different pearl types. These are only guidelines for what to expect at different scale grades, as each company has its own grading standard.
- The surface is clean with 95% and above of coverage.
- The surface has 5% or fewer slight imperfections that are not visible to the naked eye.
- The lustre is very high, with excellent to very good reflection rates.
- The surface is clean with 80-85% or more coverage.
- There is a 15-20% blemish rate.
- The lustre is high, with very good to good reflection rates.
- The surface is clean with at least 40% coverage.
- There are 50% minor blemishes and 10% deep imperfections.
- The lustre is medium, with good to fair reflection rates.
- Flaws are visible throughout the layout, with 20% deep imperfections.
- The lustre is low, with a very poor reflection rate.
- The surface is clean with minimum 95% or more coverage.
- The surface has 0-5% or fewer slight imperfections that are not visible to the naked eye.
- The lustre is very high, with excellent to very good reflection rates.
- The surface is clean with 80% or more coverage.
- There is a 20% blemish rate.
- The lustre is high, with very good to good reflection rates.
- The surface is clean with only 40% coverage.
- There are 50% minor blemishes and 10% deep imperfections.
- The lustre is medium, with good to fair reflection rates.
- The layout is marred by visible flaws, including 20% deep imperfections.
- The lustre is low, with a very poor reflection rate.
- The surface is clean with at least 95% or more coverage.
- The surface has 5% or fewer blemishes that are not visible to the naked eye.
- The nacre is very thick at 0.4mm or more.
- The lustre is very high, with excellent to very good reflection rates.
- The pearls are perfectly round.
- The pearls match almost perfectly in strands, with almost no difference between any pearl in a necklace or bracelet.
- The surface is clean with 90-95% coverage.
- The surface has minor blemishes that are not visible to the naked eye.
- The nacre is thick, at 0.4mm or more.
- The lustre is high, with a very good reflection rate.
- The pearls are round.
- The pearls match excellently to very good in strands, with little to no difference between any pearl in a necklace or bracelet.
- The surface is clean with 70-80% coverage.
- The surface has minor to medium blemishes.
- The nacre is medium thickness, but may be thin in places.
- The lustre is medium, with good to fair reflection rates.
- The pearls are round.
- The pearls match well in strands.
- The surface is clean with only 50% or less coverage.
- The surface has heavy blemishes that are visible to the naked eye.
- The nacre is thin, and the nucleus will be visible under certain lighting conditions.
- The lustre is low, with a poor reflection rate.
- The pearls are round or off-round.
- The pearls match decently in strands, but there may be some variation in colour, lustre, shape, and size in a necklace or bracelet.
- The surface is clean with minimum of 95% or more coverage.
- The surface has very minor blemishes, with 0-5% coverage.
- The lustre is very high, with excellent reflection.
- The pearls are round.
- The pearls match well in strands, with little difference between them in terms of colour, shape, size, and surface quality.
- The surface is clean with 90% or more coverage.
- The surface has minor blemishes, with 10% or less coverage.
- The lustre is high, with a very good reflection rate.
- The pearls are near round to round shape.
- Some differences in colour, shape, size, and surface quality between pearls are expected in pearl matching for strands.
- The surface is clean with only 70-80% coverage.
- The surface has minor to medium blemishes that are visible to the naked eye.
- The lustre is medium, with good to fair reflection rates.
- The pearls are visibly off-round in shape.
- The pearls match well to fairly in strands, with some differences between them in terms of colour, shape, size, and surface quality.
- The surface is clean with maximum of 50% or less coverage.
- The surface has blemishes that are visible to the naked eye.
- The lustre is low, with poor to fair reflection rates.
- The pearls are visibly off-round in shape.
- The pearls match decently in strands, with variations in colour, shape, and size.