South Sea Pearl Grading

South Sea pearls are graded much like Tahitian pearls. The two most commonly accepted systems of grading are the A-D and the A-AAA system.

We do not subscribe to superfluous grades such as AAA+ and AAAA. These are not industry accepted grades.

*South Sea pearls are known for their warm, satiny lustre which does not typically exhibit the same reflective qualities of other cultured pearls.

Characteristics South Sea Pearls

Guide to Grading South Sea Pearls

What Makes South Sea Pearls Beautiful?

LUSTRE! And the incredible natural pearl colours found nowhere else on earth!

White and Golden South Sea pearls are known to have the thickest nacre layers of all cultured saltwater pearl types, averaging between 2-4mm thick, or more.

Almost universally described by pearlers as “satiny” in look, the South Sea pearl’s lustre is generally soft in appearance. South Sea pearls radiate a gorgeous “glow” that appears to emanate from within. Occasionally features of very bright and sharp lustre occur, with almost Metallic levels of lustre.

Although colour does influence the value of South Sea pearls, it does not necessarily influence the grade. An AAA grade golden South Sea pearl of a deep naturally-gold colouration, for example, may be worth much more than an equivalent light yellow coloured pearl.

The Science behind Pearl Colour and Lustre

Like every other cultured pearl variety out there, the visual phenomenon of Body Colour, Overtone and Lustre are due to the compaction and smoothness of their crystalline nacre layers.

White and Golden South Sea pearls are both nucleated using a perfectly round mother-of-pearl bead nucleus. The nucleus is surgically placed into the gonad of the oyster, along with a tiny, 1mm square piece of donor mantle tissue from a different oyster. The incision is covered over and the oyster is placed into an “after surgery” tank for a few days while it heals from the procedure.

After a short time, the bead nucleus stimulates the formation of a pearl sac, which envelopes the nucleus in a loose “purse” and the oyster begins secreting nacre. This continues on for about 2-3 years, as the oyster continuously covers the interior bead nucleus with thousands of concentric layers of nacre and conchiolin, forming a pearl.

Nacre is the sum total accumulation of aragonite and conchiolin.

Aragonite is composed of hexagonal-shaped, semi-transparent crystal platelets made of crystalline calcium (CaCo3). These platelets are extremely small - measured in the microns!

Conchiolin is the semi-transparent to darker organic “glue” that is layered in between the aragonite platelets. Imagine that conchiolin is like the cement interspersed between bricks, holding a wall together.

White South Sea pearl conchiolin is usually colourless to light grey and pale beige, which allows the pearl to present that “bright white” appearance that is so well-loved.

Golden South Sea pearl conchiolin is present in a range of darker pigments like orange, brown and reddish-brown. This contributes to the pearl’s famous Golden colour (depending on a variety of other existing factors).

The tighter and more compact the aragonite and conchiolin layers are, the more intense the lustre, colour and orient you will perceive on the pearl’s surface.

Now that we've familiarised with how and why these various elements combine to create the visual phenomenon of "extreme beauty" to us humans, we can move onto learning the A-AAA South Sea Pearl Grading Scale.

Cultured pearls will never be as flawlessly perfect as a synthetic glass or plastic bead can be – nor should you want them to be!! Mother Nature always signs her creations, and these unique inclusions and marks can act as a built-in ID system that marks the pearls as yours and yours alone.

Intermediate South Sea Pearl Grading

You’ll often see pearls with grades that will look like "AA+/AAA Quality" and/or "AA/AA+ Quality" in their descriptions. These “intermediate” grades are given when the pearls almost-but-not-quite make it to a whole letter grade like AAA Quality.

Generally, what these intermediary grades mean is that the pearl’s surface quality (i.e. amount of inclusions) or shape is graded at a lower level like AA+, but the pearl’s lustre and shine pushes the layout to that higher grade.

It could also be the reverse in that the pearls’ surfaces are extremely clean, but the lustre isn’t quite there. However, we usually grade pearls like that with a lower anyways because what makes pearls beautiful as a gemstone? That's right! Lustre!

Common South Sea Pearl Blemishes

Inclusions are the fancy-sounding jewellery term for surface blemishes and natural growth characteristics that interrupt the smoothness of the pearl’s surfaces. In this section, we’ll break down what is and is not an inclusion (it’s not always what you think!): how these growth characteristics effect the pearl, and how they can affect value.

South Sea pearl inclusions and growth characteristics are an easy way to:

  • Ensure that the pearls are the genuine article, and not man-made fakes like shell pearls. Created synthetic pearls are usually perfect, with identical pearl beads through a layout, and feature no marks, spots, bumps, ridges, scoring or bulleting.
  • Are a built-in ID system that you can use to identify the pearls as yours and yours alone.

MOST White and Golden South Sea pearl blemishes are the colour of the corresponding nacre (so, gold or white in colour), so often these surface blemishes don’t stand out glaringly unless they’re very deep or there are a lot of them bunched together.

Mottling/Bulleting/Plating of the Surface – “Mottling” also known as “Bulleting” and sometimes “Plating” is a subtle texture on the surface of the pearl that often looks like a tiny hammer has been used to repetitively mark the pearl. This is a growth characteristic, and NOT an inclusion – it’s actually indicative of very thick nacre layering. Mottling is created in the same nacre colour as the rest of the outer surface of the pearl, and so usually can only be noticed upon up-close inspection. Bulleting does not count against a pearl’s surface grade.


Pin Pricks – Ranging in size from a tiny needle point to small pricks that look like the pearl has been poked with a pencil, pin pricks are probably the most common pearl inclusion visible today. Pin pricks can be grouped together in small clusters, or stand on their own individually, which is preferable.

Pits – These formations are pin pricks taken to extremes, and resemble large indentations, craters or even holes in the nacre. Pits count as heavy or deep blemishes when grading pearls, and their best case scenario is that they are at least the colour of the pearl, and totally covered by nacre. Worst case scenario is they are very deep and display the organic conchiolin layer; jagged, sharp edges may eventually lead to chipping.

Score Marks / Grooves - Scoring and/or groove inclusions are the second most common South Sea pearl inclusion. This resembles tiny streaks to moderately-sized channels that look “carved” in the surface nacre (often they remind me of little shooting stars or comets trailing their way across the pearl when they’re very thin and light). The shallower, the better when it comes to scoring marks, and these should also be totally covered in nacre, with smooth, unbroken edges.

Knobs and Tips – Maybe one of the most interesting-looking growth characteristic of ALL. Both tips and knobs form on the ends of the pearl (99% of the time on baroque shaped pearls). Occasionally, knobs can have additional features that resemble small bubbles. They can be rounded or elongated, pointy protrusions located at either end of a pearl. Knobs and tips are natural growth characteristics are also not counted as inclusions or blemishes. Keep an eye out for chipping or cracking however, as these vulnerable areas may affect the pearls’ long-term durability.

Circles / Circling – Originally marketed for black Tahitian pearls under the “Circles of Love” campaign in the 1980’s, “circles” are also a natural growth characteristic that does not count negatively towards the surface grade of the pearl. These are single or heavily concentrated rings running around the pearl’s entire circumference, and imbue the pearls with an incredibly unique appeal! Again, circles are NOT pearl blemishes, but blemishes can form inside them (usually in the form of tiny pin pricks or grooves).

Uneven Nacre Accumulation – Smooth, concentric and even layers of nacre producing a totally unblemished, shiny pearl surface is ideal. However, nacre building within an oyster responds to a variety of factors: environmental, temperature fluctuations, parasites, etc., can all interrupt this process to some degree or another. When the layering process is disturbed, a build-up of crystalline material can occur, resulting in bumps, ridges and uneven surfaces.

In Conclusion …

Finding that perfect White or Golden South Sea pearl for anyone is a balancing act of beauty over budget. Most South Sea pearl inclusions are small and isolated, and their colour generally will match that of the surrounding surface nacre, meaning that they’ll blend with the surface and will be only noticeable upon up-close inspection. This is especially true if the pearl’s overtones and lustre are at high levels, masking marks and distracting the eye.

When viewed through the eyes of one who appreciates pearls, pearl inclusions can become an integral facet of the pearl’s unique character. Like a snowflake, or the infamous “jardins” or “gardens” (which is the French name for inclusions in Emeralds), a pearl’s markings declare each gem as a totally unique and individual creation of Mother Nature.

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