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Quality Standards & Pearl Grading Guide

One of the biggest difficulties for consumers and vendors alike in the world of pearls is that there exists no standard grading system for pearls. Each vendor is free to come up with their own grading standards for pearls -- one vendor's "A" may be equivalent to another's "AAA"

That stated, the following information and education attempts to display quality markers of various types of pearls, and also serves to showcase how Moline branded pearls are graded and chosen, in order of most to least important quality. 


Luster is loosely defined as the sharpness of reflections on a pearl surface. The strength of luster does vary among pearl types: The best Akoya pearls, cultured in cooler waters usually near Japan, tend to have a stronger luster than other pearl types even in highest quality examples.

Luster is also not always cross-comparable. Darker Tahitian pearls, for example, can have a stronger and deeper looking luster because of their darker tones than a lighter colored Tahitian pearl may be able to display. 

Luster is considered the most sought after quality in any type of pearl, and the top luster pearls command premium prices. 

Surface Quality

Surface quality is defined as the number (or lack thereof) of blemishes on a pearl's surface, as well as its overall surface texture. The smoother, more glossy of a texture that a pearl's surface has, the more desirable the surface would be considered. In addition to outward surface characteristics, a pearl's skin also has "tightness." The tighter the skin of a pearl, the more contrasted and vivid its luster will appear.

It's important to note that many pearls often have a slight surface texture that is often described as "orange skin" or "shark skin" texture. While an ultra-smooth texture is most preferred and commands the highest price premium, it's noteworthy that such slight "shark" or "orange skin" surface textures are not considered undesirable or indicating of a lower quality pearl. A pearl can still have top quality luster with a slightly textured surface.



It surprises many to learn that very few pearls in a harvest (< 5%) are actually truly round. For us, a pearl's shape is usually categorized into eight types: round, near-round, semi-round, button, drop, oval, baroque, and circled.

As you may notice, there are three different technical categories of "round," so buyers must be very cautious where a pearl's shape is concerned. Some vendors and even wholesalers will describe pearls as "round" that may be slightly off shape, or describe a strand as round even when it contains some pearls within that are not truly round -- and there is often a very significant price difference between true round pearls and those that are even just near-round. When shopping for pearls, ensure that any pearls described as "round" are in fact true round, and any strands described as round actually comprise of all completely round pearls. 

All Moline Pearls studs and strands described as round are, in fact, all true round pearls. 


Color and tone vary by pearl type. Nearly universally, a slight to medium strength pink tone is considered highly desirable in Akoya and South Sea pearl types. 

Unique and vivid orient (the "soap bubble" effect sometimes seen on a pearl's surface) and colorful overtones on a pearl contribute to its value, but in many cases overall color of a pearl can be down to personal or cultural preference. 


Sometimes a particular piece can include mismatched pearls for a particular design. Overall, though, pearls in earrings and strands should match well across the above quality factors. 

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