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Pearl grading system


Pearl grading is very similar to the "4 C's" of diamond grading in that the pearl grading system takes into consideration several key categories of qualitative comparison analysis. The pearl grading system consists of five main categories:

1. Luster

A pearl's "luster" is one of its most important physical attributes, and the highest determining factor in grading and valuation after its regional origin. A highly 'lustrous' baroque pearl is probably more desirable than a perfectly round pearl with an opaque, or "milky" surface lustre. The quality and depth of a pearl's nacre gives the "lustrous" quality for which pearls are valued. To explain it simply, luster refers to how "shiny" or "dull" a pearls is:

  • Low lustre: Pearls surface appears "chalky" and/or "milky."
  • High lustre: Pearl surface reflects light and shows mirror-like reflections.
2. Shape

Shape is one of the principle determining factors in a pearl's value after luster. With all other factors being equal, the general rule is that the rounder the pearl, the more valuable it is. Pearls come in a wide variety of shapes, each having a specific designation.

3. Color
Pearls come in a wide range of natural colors (hues) and shades (tones), but some pearls are dyed or irradiated to suit a specific fashion trend or requirement. Naturally occurring pearl colors include traditional white as well as fancy silver, cream, pink, lilac, silver and gold hues.
4. Surface
Surface blemishes, or the lack thereof, play an important role in the valuation of pearls. Generally speaking, the fewer surface blemishes a pearl has, the more valuable it is. The term "blemishes" refers to any visible bumps, marks, imperfections or small indentations on the pearl's surface. These blemishes give each pearl a unique "fingerprint" of identifying factors.
5. Size
Generally speaking, the larger the size of the pearl, the greater its value. Large pearls not only require larger oysters to produce them, but they require much more time to develop inside the oyster, depending on the size of the nucleus. An average-sized pearl can take 2 to 3 years to develop. Significantly larger pearls can take twice as long to grow. Additionally, it is very difficult to maintain a perfectly spherical shape while the pearl develops. This is why very large round pearls are extremely rare and valuable.