Freshwater Pearl Basics

Freshwater pearls cover a wider range of color and shape than any other pearl type. Originally these pearls were marketed as a lower quality, inexpensive alternative to Akoya pearls. For this reason, jewelry designers traditionally used freshwater pearls for pieces that favored design over the gems themselves. However, since the 1990s, a class of freshwater pearls that are round and lustrous have emerged which rival Akoya pearls in both quality and value. Freshwater pearls cover the widest range of options for pearl buyers in size, shape and color.

Freshwater Pearl Culturing

Most freshwater pearls that are produced today come from the Hyriopsis Cumingi (triangle shell) species. This species yield higher quality pearls than the C. Plicata species, which was used throughout the 1980s.

Unlike cultured saltwater pearls, freshwater pearls are not bead-nucleated and are therefore typically less round. Instead of using a bead, a small square of mantle tissue is cut from a donor mussel's inner lining and inserted into the lining of the harvesting mussel to instigate pearl formation.

The unique harvesting technique makes freshwater pearls purely composed of nacre. Nacre is the biological term used to describe the mother of pearl substance that gives pearls their distinguishing glow. It also is one of the main value factors for grading all pearl types. Because cultured saltwater pearls are bead nucleated, their nacre thickness ranges between 0.2 mm and 4.0mm.

Freshwater Pearl Characteristics

The unique culturing method also means that freshwater mussels will never produce a perfectly round pearl. When beads are used in nucleation, rounder pearls accumulate much easier. This has historically been the largest trade off between tissue nucleated and bead nucleated. Tissue-nucleated freshwater pearls are more natural and composed purely of nacre; Bead nucleated saltwater pearls have superior shape and create more uniform strands of pearls.

Only two percent of all freshwater pearls are round or near round. Though this number seems quite small, the abundance of freshwater pearls is much greater than other pearl types. Each freshwater mussel will produce up to 40 pearls, whereas one saltwater mollusk usually only produces one or two pearls.

The most common shape in freshwater pearls is oval or button shaped (sixty percent). Thirty-eight percent are Baroque and Semi-baroque. Almost all Freshwater pearls come from China. Since the 1990s, Freshwater pearl quality has steadily increased. Though you never will have a perfectly round Freshwater pearl, the likelihood of finding a quality near round pearl is much greater today.

Freshwater Pearl Sizes

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Freshwater pearls range from 2.0 mm to 15.0. They have the widest size range of any pearl type.

6.0-7.0mm pearls are best for petite persons or those wishing to maintain an understated, minimalist appeal. Because the pearls are smaller, often times it is more likely to have rounder freshwater pearls.

7.0-8.0mm pearls are slightly more substantial, while still making a refined statement.

9.0-10.0mm pearls are about the size of an eraser head on a No. 2 pencil. They are well suited for young adults or mature teens.

10.0+mm freshwater pearls are often not as consistent in shape and size due to the rarity of their occurrence. Furthermore, it is even less likely that a larger freshwater pearl will be round. For these reasons, this size range tends to highlight the natural cultivation process of Freshwater pearls.

Freshwater Pearl Colors

freshwater pearl colors

Freshwater pearls produce the widest array of colors and shapes. There are dozens of naturally occurring colors found in freshwater pearls. Their body color can be white, cream or colored (yellow, orange, pink and purple). Above are the 4 most common colors seen on the retail market today but by no means illustrate the full spectrum of possible colors. Freshwater pearls are rich in orient, an optical effect where rainbows of colors shimmer beneath the pearl's surface. This effect is similar to shifting rainbows reflecting on soap bubbles. Orient is commonly found in freshwater pearls due to their composition of pure nacre. When freshwater pearls are dyed black, it enhances the orient and results in dark pools of color, similar to gasoline on pavement.

Freshwater Pearl Overtones

Freshwater pearls have overtones, but they are different from bead-nucleated pearls. Typically freshwater pearls of lower quality show little to no overtone, though higher quality freshwater pearls can show overtones of rose, blue and green.

Freshwater Pearl Grading

Gem(formally presidential line), AAA & AA+
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This system grades pearls on a scale from A to AAA, with an additional grade being given to extremely rare and high quality gem grade pearls.

Grade Description
Gem Quality Round to the eye.  Supreme luster with excellent matching and clean surface quality >95% blemish free. 
AAA Near round to the eye.  Brilliant luster, 80-90% free of any blemishes or marks. 
AA Medium luster with surface defects over not more than 60% of the surface area.
A Noticeably off round. Very little to no luster, 70-90% free of any blemishes or marks.