Pearl Value Factors


It is Week 3 of the month with the best birthstone, Pearl. With every pearl being created by an individual organism, affected by various environmental conditions, quality of care, culturing time, and overall health of the mollusk, every pearl needs to be evaluated individually. So how do we evaluate pearls?

This week, let's take a look at the Pearl Value Factors and the nuances that go into determining a great pearl from a good pearl from a nasty pearl. There is no universal system for evaluating pearls like there is with diamonds, but by using these guiding principles, we can consider each pearl and create beautiful jewelry.

#1: Size

Pearl size refers to the diameter dimension of the pearl and it is expressed in millimeters (mm).

It doesn't matter what they told you: Size Matters. All other value factors being equal, a larger pearl will be more valuable.

Pearl size is dependent on several factors:

  1. The mollusk species—some mollusks can grow larger pearl than others

  2. The size & health of the mollusk (Bigger/Better = Bigger)

  3. The size of the bead nucleus (Bigger = Bigger)

  4. Length of time the mollusk stays underwater (Longer = Bigger)

  5. Climate and nutrient conditions of the growing environment (Consistently Good = Bigger)


Pearl Size Chart

#2: Shape

The pearl shape is the silhouette of the pearl, which ranges from round to baroque. There are three distinct shape categories: Spherical, Symmetrical, and Baroque.

For any shape other than the three major categories, the shape is described as it appears (coin, stick, button, etc).

A pearls shape is dependent on several factors:

  1. The shape of the bead nucleus

  2. Length of time the mollusk stays in water (Longer = Less predictable and less round)

  3. Climate and nutrient conditions of the growing environment

The longer the pearl remains within the mollusk, the greater the chance of developing an irregular shape. A perfectly round pearl is very rare. Even if the bead nucleus is round, the pearl may not grow evenly in all directions. A large, perfectly round pearl is even rarer!


Pearl Shape Chart


#3: Color

Pearls come in a wide range of colors resultant of the breed of the host mollusk and that of the donor tissue. The pearl will likely be similar in color to the mother-of-pearl lip of the mollusk in which it forms. There are a host of external influences, including diet, water temperature and pollutants., that can effect the color of the pearl, making it impossible to accurately predict the color of the pearl.

Pearl color is a combination of three elements:

Body colors: Body color is the dominant hue of a pearl. What color do you see when you just glance at the pearl? Overtones: Translucent color that overlies bodycolor. If you tilt the pearl from side to side and squint, is there a slight tinge of a secondary color? Orient: Iridescent rainbow colors on the surface. This is the magical, rainbow wash you see when you look at a pearl.

All pearls have a body color, but not every pearl displays overtone and/or orient.

#4: Luster

Luster is what pearls do best. Luster is the way the light plays off of the surface of the pearl. Due to the pearls' nacre structure, light does not just reflect off of the surface of the pearl. Rather, light penetrates the surface and seems to reflect from WITHIN the pearl. The way that a pearl seems to emit light is its luster.

The quality of the nacre dictates the quality of the luster, which is very important to its beauty and its value. Pearl farmers can control the quality of nacre only to an extent. For example, allowing the pearl to form for more time will tend to make the nacre thicker and harvesting pearls during cold weather can often improve final luster quality! Many environmental factors can interrupt or alter the nacre formation, so there is no fool-proof method for creating a beautiful luster.


Pearl Luster

#5: Surface Complexion

Like other gemstones, pearls have clarity characteristics, but since pearls are not transparent or translucent, clarity is confined to the surface as blemishes in the surface complexion. Surface complexion is defined by the degree and visibility of surface imperfections. The fewer blemishes, the better the surface complexion.

Pearl blemishes that are often seen include: Pits, Abrasions, Bumps, Ridges, Chips, Cracks, Flat areas, spots, or uneven nacre coating.

Surface complexion is categorized using the terms: clean, lightly blemished, moderately blemished, heavily blemished.

A spotless pearl is extremely rare and valuable. If, for example, a pearl is large with excellent luster, these qualities will outweigh minor surface imperfections. Large or numerous imperfections not only lower the value, but can affect durability and the ability to see a pearl’s luster as well.


Pearl Surface Complexion

#6: Nacre Quality

The only way to determine the exact thickness of the nacre is to x-ray the pearl or cut it in half (I don't recommend cutting your pearls in half!). However, there are ways that we can visually assess the nacre quality.