Always consider the grading system when selecting pearl necklaces or earrings. Look for the Mikimoto grading standard which has been the adopted international standard for decades. Most conventional retailers do not discuss the grade of their strands as mostly they are unaware of the significant difference in value between grades.
Pearl Grades vary as typical grading is AAA, AA+, AA, A, B, C. Most quality retailers do not carry any pearls under an "AA" grading. Only look for quality retailers that understand pearls and grade the pearls in a professional manner.
The following is typical Mikimoto style Grading and Specification of a pearl necklace in Superior Quality Akoya Pearls:
Luster: AAA outstanding Thick Nacre
Body surface: AAA Minimum 95% Clean
Shape: AAA Matching Outstanding Round
Stringing: Knotted Fine Silk Double Threaded
Pearl Type: Akoya Saltwater Cultured Pearls
Length: 18 inches
Size: 7.0 - 7.5mm
Clasp: Solid 14K Yellow Gold
Please note that the overall grading in this example should be a "AAA" quality strand. Had one of the categories been less than "AAA" then an Evaluation and Appraisal Team should normally decide whether or not to re-grade this piece of pearl jewelry. Always choose a store that will describe their pearl necklaces in this amount of detail. This is how you can determine the true worth of a pearl and your purchase.
Freshwater Pearl Grading
Freshwater pearls are graded by several factors. The difference between AA+ and AAA are as follows:
AA+ Freshwater Pearls shape: off round; they look generally round from over 3 feet away, but from up close you can tell they are not perfectly round.
AAA Freshwater Pearls shape: visibly round; they look round from 8 to 12 inches away. They may have a slight deviation from round if you measure them with jewellers callipers but you wouldn't notice it unless you specifically analyzed them up close.
AA+ Freshwater Pearls will often have excellent luster. AAA Freshwater Pearls will always have excellent luster. Any qualities lower than AA+ will generally have less luster.
AA+ Freshwater Pearls will have at least 90% of the surface of the pearl unblemished. Small surface irregularities are a natural part of all pearls, but most of these are only seen with a magnifying glass or under careful examination in very good light. Upon close examination they would look like tiny variations of color, indentations or bumps - all about the size of a pin prick and very shallow.
AAA Freshwater Pearls will have at least 95% of the surface of the pearl unblemished. Any small surface irregularities will not be noticeable except with careful examination in very good light and with a magnifying glass or really good eyesight! They do not detract from the beauty of the pearls.
Don’t be fooled by expensive claims like “collectors’ quality”, “AAA+” or even “AAAA quality” pearls. These are simply marketing techniques used to oversell inferior pearls and drive prices up. Clearly look for the Mikimoto standard in grading and quality control. AAA is simply the best grading on the market under this original standard rating system. There are many excellent retailers on the internet that use this old reliable rating technique to grade their pearl necklaces.