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Pearls! The Value Characteristics, Part I

Image courtesy of CPAA

As we’ve looked at pearls so far, we have explored their formation (Natural vs. Cultured), had an overview of their History, and looked at potential options to assist with selecting the perfect pearls for you or a loved one to accentuate skin tones. All of these are fascinating and fun, but how do we know what we are getting as a pearl? Can we compare them across the board to cut gemstones as far as grading goes? Is there a universal standard? Unfortunately, not yet. So how do you know what to look for? How do you trust what you are buying? First, it helps to buy from someone you trust. Building that relationship with someone who is able and willing to answer your questions and help you begin to recognize what you are looking for and at really boosts your buyer’s confidence and also helps with your own knowledge base. That can take time, though, and sometimes you see something at a fair from an artist who came from far away and you REALLY feel that pair of earrings will make the PERFECT gift! But how do you know how to judge them yourself? Read on for more info!

As with other gemstones, grading pearls comes from looking at a group of criteria, and then figuring out how they weigh in for each category and overall. The challenge with this comes in when you learn that not everyone rates pearls the same way, or even uses the same terminology for the grading. One house/importer/wholesaler/shop may use an A-D scale (with A being high quality and D being low) while another may use an AAA-A scale, while yet another may use AAA+ through A- or even D- (I saw an A- - rating once that looked like what I had learned was a C!). Are you confused, yet? I sure was! So I was VERY glad to learn that places like the Gemological Institute of America(GIA) have a group of 7 characteristics they use when giving pearls their grade. I want you to be able to shop with confidence, so let’s go through these characteristics and talk about what we are looking at.

The 7 Pearl Value Factors used by the GIA are: Size, Shape, Color, Nacre, Luster, Surface and Matching. These can shift in weight depending on the type of pearl being examined, but once you understand what you are looking at in general, it helps a lot. Since I work with freshwater pearls, this is where we will focus for now. In this post I will share about the first 3 Value Factors, and in the next post I will discuss the last 4. I will happily share information on other pearls later on.

As they pertain to freshwater pearls, the Value Factors are:

Image courtesy of GIA


The Luster a pearl shows is the quantity and quality of light that reflects from the surface (and just under the surface) of the pearl. This is the most important Value Factor – when all others are equal, the higher the quality of the luster, the higher the value of the pearl. These can range from a dull finish all the way to bright metallic, mirror-like shine. The mirror-like appearance is more frequently found with darker or naturally pastel pearls, but it does happen with white as well.

Image courtesy of CPAA


There is a vast array of shapes to be discovered with freshwater pearls – everything from the traditionally coveted – and extremely rare - perfectly round all way to fireball and souffle(both styles of baroque) with potato, rice, stick, button, cube, and more in between. With bead nucleation, the seed that is implanted determines to a great extent the shaping of the pearl. Potato and rice are more oval in shape, buttons are disc-shaped, and baroque are the most commonly produced. This last group is asymmetrical, so it is very obvious that each pearl is its own unique work of art.


The sizing of a pearl is determined by the growth time in the mollusk, which can vary greatly from pearl to pearl. While the largest pearls tend to be baroque(with some specimen being recorded at 55mm), the most common sizes range from 6-12mm. There are also freshwater pearls smaller than a single millimeter, and these are often referred to as “seed pearls.”

In the next post, I will share about Nacre, Surface, Color, and Matching.

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