Pearl Grading | Freshwater, Tahitian, & Akoya Pearls
Pearl Grading System
Pearl grading is very similar to the 4C's of diamond grading in that it takes into consideration several categories of qualitative comparisons. The pearl grading system consists of five main parts. They are:
Although size will certainly play an important roll in evaluating the monetary value of a pearl, luster, shape, color, and surface quality are of primary importance. Each of these five steps are explained in detail in the following text.
Unfortunately, the pearl industry as a whole has not adopted a universally used standard grading system. Instead, the specific grading system used often depends upon the specific jeweler or pearl distributor.
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Two major grading systems are in fairly widespread use: the 'AAA-A Grading System' and the 'A-D Grading System' - also called the Tahitian grading system. These are the most universally accepted standardized systems, and are used by nearly all reputable retail and wholesale pearl dealers.
The AAA-A Pearl Grading System
This system grades pearls on a scale from AAA to A, with AAA being the highest grade, this grading scale is common to freshwater and akoya pearls only, but is accepted by many South Sea and Tahitian pearl dealers. The AAA to A grades are as follows:
- AAA: Virtually flawless pearl. Surface luster is very high , and 95% of surface will be free from any defect.
- AA: The surface will have a very high luster, and at least 75% of the surface will be free from any type of defect.
- A: The lowest jewelry-grade pearl, with low surface luster and/or more than 25% of the surface showing defects.
The A-D Pearl Grading System
This grading system grades pearls on a scale from A to D, with A being the highest grade. This system is used in French Polynesia to grade Tahitian pearls, and South Sea pearls only. This is why it is referred to as the "Tahitian system." While this system is standard in producing countries, other markets will use the AAA-A System.
- A: Highest-quality pearl, very high luster and only minor imperfections over less than 10% of its surface.
- B: High or medium luster. Surface may have some visible imperfections over no more than 30% of its surface area.
- C: Medium luster with surface defects over not more than 60% of the surface area.
- D: May have many slight defects over 60% of surface or deep defects over no more than 60% of surface.
Pearls of the "D" variety may have a combination of minor and deep defects over no more than 60% of its surface. In this grade of pearl, the luster is irrelevant. Even the most lustrous pearls will be graded D if their surface ares is blemished to this extent.
Pearls below D grade are considered not acceptable for use in jewelry.
Both of these grading systems focus primarily on the luster and surface quality of the pearl to determine its grade. There are however, other factors that contribute to the quality and value of any pearl.
One of the most important non-graded factors is the thickness of the nacre, which will determine how durable the pearl will be over time. The thicker the nacre, the longer-lasting and more durable the pearl. For Tahitian pearls, the government of French Polynesia has set a minimum nacre thickness of 0.8 millimeters. Any pearls with nacre of less than that thickness are not allowed to be sold.
Synthetic Pearls
Synthetic Pearls (aka faux pearls) can be made of totally synthetic materials such as glass or plastic, or natural materials such as pulverized mollusk shells used to coat 'mother-of-pearl shell beads.' The so-called "tooth test" was one way of differentiating natural or cultured pearls from synthetic faux pearls, but this test can have mixed results. The tooth test is done by rubbing a pearl along the biting edge of your front tooth to detect any grittiness found in a natural pearl.
Majorica Simulated Pearls started by Eduard Hugo Heusch in the late 19th century are made in Manacor on the island of Mallorca Spain. The Majorica Pearl is made with an opaque glass nucleus dipped in a solution made from fish scales. Up to 30 layers of this pearlescent coating are applied to simulate the natural pearl lustre.
Swarovski Crystal Pearls, made by Swarovski of Austria, are a glass pearl simulant made with a leaded crystal core and a coating that gives them a lustre similar to natural pearls.
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