Pearls are unique among gemstones in that they are natural, organic products of living creatures, so they have different grading standards. We want our customers to make informed decisions when they buy pearls from us. With this in mind, We have put together this illustrated guide to help answer some of the most common questions about pearls. Nanzhu Shijia uses the most commonly used and internationally recognized ranking system: A, A+, AA, AA+, and AAA to grade the pearls featured on our website. On this scale, AAA is top-quality, the absolute highest quality pearl available. Six factors determine the quality、value and beauty of pearls: nacre、luster、surface、shape、 color and size.
　　Type of Pearl
　　The first step is to identify the type of pearl-freshwater or Sea pearl, the two main pearl types used in jewelry. Each type of pearl is produced by a different species of oyster, and each oyster lives in a different region of the world under very specific climatic conditions.
　　Pearl Nacre
　　Nacre is the natural substance that the mollusk secretes to protect its sensitive flesh from irritants such as shell fragments or implanted beads. This is the same beautiful iridescent material that lines the inner surface of the oyster shells, aptly named mother-of-pearl. As a rule, the thicker the nacre, the higher quality the pearl is.
　　Pearl Luster
　　Luster is a combination of surface brilliance and a deep glow. The luster of good quality pearls should be bright. You should be able to see your reflection clearly on the surface of a pearl. Any pearl that appears too white, dull or chalky is of low quality.
　　Other quality factors: Pearl surface, Pearl Shape, Pearl Color and Pearl Size. The perfect shape and bigger the better.