How to Grade Pearls for Jewellery

Pearls are not something that typically feature in your average engagement ring. In saying that, they are popular in many different pieces of jewellery you can buy. However, if you’re wondering why some jewellery is expensive, while others are not, then it can come down to the pearl quality. How do you grade pearls for jewellery, and why are there different grades to begin with?

How Pearls are Made

To understand how to grade pearls for jewellery, it’s worth understanding how they are made in the first place. A mussel, clam, or oyster may find itself in contact with an irritant, such as a parasite, that it wants to get rid of it. It covers it in a liquid known as nacre as a form of defence against that parasite.

It will keep coating that irritant with nacre over time until it forms the pearl. Humans now get involved in the process to keep a steady supply of pearls by inserting irritants into oysters, clams, and mussels, and controlling the whole pearl creation process.

In saying that, some pearls are not pearls at all, but rather, imitation pearls. They tend to be glass balls that the manufacturer coat in a fish scale colouring to make them look like pearls. You can tell the difference between a real and fake pearl by scraping your teeth along them. A fake pearl is gritty, and the coating may even come off. A natural or genuine pearl runs smoothly through your teeth.

How to Grade Pearls

The pearl grading system takes into account any surface blemishes, the pearl’s shape, and the lustre (the sharpness of the reflections). The most commonly used grading system for freshwater pearls is A-AAA, but South Sea grading tends to be from A-D, which is what pearl farmers often use.

In the A-AAA system, the best pearl you can buy is AAA. This pearl type is 95%+ blemish-free with a mirror-like lustre and a near-perfect round shape. As those features lessen, they get a less perfect grading, such as AA+, AA, and A.

In the South Sea grading system, the pearls are graded from A to D. A is 90%+ blemish-free, which means the pearls are suitable for rings, pendants, and earrings. They have a sharp luster, and they reflect sharp and crisp light sources.

At the lower end of the scale, a D-graded pearl would have a 40% blemish-free surface, with the remaining 60% featuring blemishes. They will also have little to no luster and will more likely look dull or chalky.

Pearls of this grade tend to be recycled, rather than sold, as they are not suitable for export. They make up around 35% of the annual yield.

If you’re looking for the perfect piece of jewellery for your loved one, then understanding how the grading system for pearls works can make all the difference. You may come to realise why you pay more for a high-quality pearl, and how to notice whether one isn’t as high-quality as you may have thought.