How do you judge the value of a pearl?
Pearls are a natural product and (like hand-blown glassware) small imperfections are quite acceptable. Perfectly round are rare - accounting for only a tiny percentage of the millions harvested each year. Such pearls are usually referred to being of 'gem' quality.
Grading (e.g. A, AA, AAA) takes into account size, shape, lustre, surface quality, color, and matching on the strand. There is no international standard for grading, and identical pearls may be graded differently by different suppliers.
| GRADE | A | AA | AAA |
| Lustre | medium to good | good to high | high |
| Blemishes | light | slightly | slight to clean |
| Shape | slightly off round to round | slightly off round to mostly round | round |
| Matching | good | good to very good | very good |
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To complicate matters further, not all the criteria apply to all the pearls on a strand. For example, even on a AAA grade strand, some pearls may exhibit small blemishes, others will be clean. Grading takes into account both the degree of blemish and the proportation of blemishes on a strand.
Pearls sizes are quoted in millimeters (e.g. 7mm-7.5mm). Size variation within these measurements are acceptable.
If you are buying a good quality pearls necklace don't just try it on for size. Examine it carefully. A sixteen inch necklace of 7mm pearls will have about 50 pearls on it. How well are they matched in terms of shape, size, and lustre? Turn the necklace around and see how it looks from different angles. Is that match still Good?
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