Pearls come in such a variety of shapes, colors, sizes and types that it would be tough to agree upon a fair price for buying and selling without some type of grading system. Pearls have two grading systems that are acceptable to use throughout the industry. One is the AAA-A system and the other is the A-D system, also known as the Tahitian system. The AAA-A system is most common with freshwater and akoya pearls, although it can be used for pearls of any type. The A-D System is used only when assessing Tahitian and South Sea pearls
How the Grading Systems Work
While the systems use different overall grades to rate a pearl, they both look at some of the same characteristics that determine a pearl’s quality. Not every characteristic gets equal weight in the grading systems, with the two most important being:
Luster: Bright, highly reflective pearls get the higher rating
Surface clarity: Surface blemishes are rated by their size, number, type and location, with higher ratings going to pearls with fewer, less obvious blemishes.
Other factors that contribute to a pearl’s overall grade include:
Nacre thickness: The thicker the nacre, the higher the value
Color: White and grey-white are usually at the top of the scale, although specific tastes may dictate otherwise
Size: Larger is typically more valuable
Shape: Roundness and symmetry are generally most prized
Matching: Refers to specific way pearls are matched up strung to produce the most uniform arrangement in the way of shape, color, luster, spotting and graduation.
Grading is also relative to each pearl type, and different types of pearls are never graded against each other.
The AAA-A System
This grading system ranks pearls from AAA to A, with AAA being the highest.
AAA: Nearly flawless pearls with a high luster and a surface that’s 95 percent free of defects
AA: High luster with a surface that’s 75 percent free of defects
A: Lower luster and defects on more than 25 percent of the surface.
The A-D System, or Tahitian System
A is the highest grade in this system, with D being the lowest. The A-D system is based on a French Polynesian government standard and sometimes substituted by the AAA-A system in other parts of the world.
A: Very high luster and defects on less than 10 percent of the surface
B: High to medium luster and defects on less than 30 percent of the surface
C: Medium luster and defects on less than 60 percent of the surface
D: The lowest rating doesn’t look at luster but only surface defects. This rating can apply to pearls with:
Slight, but not deep defects on up to 60 percent of its surface
Deep defects over no more than 60 percent of its surface
A combination of slight and deep defects over no more than 60 percent of its surface
Pearl grading is one more tool you can use while shopping for your perfect pearl to ensure you get the highest quality gem for the price.