Freshwater Pearl Beads: Shapes, Sizes and Hole Sizes
Freshwater pearl beads are cultured pearls grown in freshwater mussels, almost all of them in China, and they come in more shapes than any other pearl: round and near round, potato, rice, button, coin, keshi, baroque and stick, plus top-drilled pearls for drops. Most are solid nacre with no bead at the center, which keeps them affordable and lets them grow in sizes from 2 mm to 20 mm and more. Their holes are small, usually well under 1 mm, so they are strung on silk, fine beading wire or thread. Here is each shape, how sizes and colors work, and what fits through the holes.
Our freshwater pearl beads include tiny semi round pearls, potato and off round strands, button pearls, baroques and biwa sticks, in white and peacock.
What Are Freshwater Pearls?
A freshwater pearl grows inside a mussel raised in a lake or pond. To start one, a pearl farmer slips a small piece of mantle tissue from a donor mussel into the mussel's own mantle. The tissue forms a pearl sac that lays down nacre inside itself, layer by layer: microscopic plates of aragonite, a form of calcium carbonate, bound with a protein called conchiolin. A single mussel can grow dozens of pearls at once, and most of today's freshwater pearls come from the triangle shell mussel, Hyriopsis cumingii, farmed in China.
Because there is usually no shell bead inside, a freshwater pearl is almost entirely nacre. That is why so few come out perfectly round, and why the shapes are so varied. Saltwater pearls such as Akoya, Tahitian and South Sea grow in oysters around a round shell bead, usually 1 or 2 at a time, so they are rounder and cost more. Freshwater pearl culturing took off at Lake Biwa in Japan in the 20th century, which is where biwa stick pearls get their name.
Cultured does not mean imitation. A cultured pearl is a real pearl made by a living mussel; the farmer only starts the process.
Freshwater Pearl Shapes at a Glance
| Shape | Typical sizes | Best uses |
|---|---|---|
| Round and near round | 2 mm to 10 mm | Classic knotted strands, spacers, earring drops |
| Potato | 4 mm to 9 mm | Everyday necklaces and bracelets with a classic look |
| Rice | 3 mm to 7 mm | Delicate layering strands, multi-strand designs |
| Button | 4 mm to 10 mm | Bracelets, earrings, necklaces that lie flat |
| Coin | 10 mm to 20 mm | Statement necklaces and earrings |
| Keshi | 4 mm to 20 mm | Organic and textured designs |
| Baroque | 5 mm to 20 mm and up | Modern and boho pieces, focal pearls |
| Stick (biwa) | About 4 mm wide, 15 mm to 30 mm long | Fringe, collars, mixing with rounds |
| Top-drilled | 6 mm to 15 mm | Earrings, pendants, drops and fringe |
Freshwater Pearl Shapes
Round and Near Round
Perfectly round freshwater pearls are the hardest to grow and make the classic strand. Near round pearls, also sold as semi round or off round, look round on the strand but roll a little unevenly, and they make up most "round" freshwater strands. We carry tiny 2.3 mm and 2.5 mm semi round white pearls and 6 mm off round peacock pearls.
Potato
Potato pearls are slightly oval with softly flattened sides. They give the look of a classic strand at a lower cost than round, and ours include 7 mm to 8 mm peacock potato pearls.
Rice
Rice pearls are long ovals, longer than they are wide, drilled end to end. They are usually small and make fine layering strands.
Button
Button pearls have a round outline with 1 or both sides flattened, like a button. Our 8 mm white button pearls have a bright luster that suits bracelets and earrings.
Coin
Coin pearls are flat discs, usually 10 mm and larger, with a broad face that shows off their luster. They are usually drilled from edge to edge so the flat face shows when strung.
Keshi
Keshi is Japanese for poppy seed. The word first meant the small, all-nacre pearls that form by accident during culturing; in freshwater beads it is now used for irregular pearls, often petal or cornflake shaped, with high luster.
Baroque
Baroque covers any irregular shape, from lumps and ridges to drops, so no 2 pearls match. Baroques often have the strongest luster of all. We carry 6 mm white baroque pearls and small 3 mm baroque semi rounds.
Stick (Biwa)
Stick pearls are long, slender and flat, with ripples and bends, and are sold as biwa pearls after the Japanese lake. Strung side by side they make fringe and collars. Ours are white biwa sticks 4 mm to 5 mm wide.
Top-Drilled
Any shape, most often a teardrop, potato or coin, can be top drilled: the hole runs across the narrow top instead of through the body, so the pearl hangs as a drop for earrings, pendants and fringe. Larger fancy shapes such as teardrops, ovals and rectangles also come in the 14 mm to 18 mm range.
Pearl Sizes
Pearls are measured in millimeters across their widest point. Long shapes get 2 numbers, width by length, so a 14x18 mm teardrop is 14 mm wide and 18 mm long. Because every pearl is slightly different, strands are often sold as a range, such as 7 mm to 8 mm. For a sense of scale, a 15 inch strand of 2.5 mm pearls holds about 150 pearls, while a strand of 8 mm pearls holds about 45 to 50.
Luster and Surface
Luster is the bright, mirror-like glow that comes from light reflecting off the thin layers of nacre, and it is the first thing to look at in a pearl. Sharp, bright reflections mean fine, even nacre; a chalky surface means less glow. Freshwater pearls also carry small surface marks, such as tiny pits, spots, ripples and rings around the body, which are part of how a pearl grows. Cleaner surfaces, rounder shapes and higher luster are what make one strand cost more than another.
Freshwater Pearl Colors
Freshwater mussels grow pearls in a soft palette: white, cream, peach, pink and lavender, often with an overtone, a second color such as rose or silver that floats over the body color. Our white strands run from silvery white to creamy white.
Freshwater pearls also come in darker and brighter colors, such as peacock, black, blue, red and vivid yellow. Ours include peacock potato pearls and off round peacock pearls.
Hole Sizes and What Fits Through
Pearls are drilled with small holes to keep as much nacre as possible. Hole size is not standardized, but most pearl holes are well under 1 mm, and our freshwater strands list 0.3 to 0.4 mm. That is smaller than the hole in most gemstone beads, so check your stringing material before you start:
- Silk: Griffin silk in size 0 (0.3 mm), 1 (0.35 mm) or 2 (0.45 mm), the traditional choice for knotted strands.
- Beading wire: .010 or .012 inch (0.25 or 0.30 mm) stringing wire, or .015 inch (0.38 mm) when the holes allow, finished with crimps.
- Needles: the needle attached to a silk card, or a fine flexible beading needle; see choosing the correct beading needle.
- Elastic: 0.5 mm elastic is usually too thick for holes this small.
If a hole is too tight, a bead reamer can open it slightly; work slowly from both ends so the nacre does not chip. For step by step stringing, see How to Knot Pearls with Silk Cord.
Pearl as a June Birthstone
Pearl is a birthstone for June, alongside moonstone and alexandrite, and the traditional gift for a 30th wedding anniversary. See our June birthstone beads.
Caring for Pearls
Pearls are soft, about 2.5 to 4.5 on the Mohs scale, and acids dull their nacre, so put them on after perfume, hairspray and lotion, wipe them with a soft cloth after wearing, and store them apart from harder gemstones that can scratch them. How to Care for Pearl and Amber Jewelry covers cleaning and storage in detail.
Frequently Asked Questions
Are freshwater pearls real pearls?
Yes. They are cultured pearls, grown by living mussels after a farmer inserts a small piece of tissue. Imitation pearls are glass or plastic beads with a pearly coating.
What is the difference between freshwater and saltwater pearls?
Freshwater pearls grow in mussels, many at a time, and are usually solid nacre, so they come in more shapes and cost less. Saltwater pearls such as Akoya grow in oysters around a shell bead, 1 or 2 at a time, and are more often round.
What size pearls are best for a necklace?
The classic single strand is 6 mm to 8 mm. Pearls of 2 mm to 4 mm look delicate and layer well, while 9 mm and larger make a statement.
What size holes do freshwater pearls have?
Usually well under 1 mm; our freshwater strands list 0.3 to 0.4 mm. Griffin silk sizes 0 to 2 and .010 or .012 inch beading wire fit most of them.
Why are freshwater pearls not perfectly round?
Most grow from a small piece of tissue rather than a round bead, so nothing guides them into a sphere. Round ones are the hardest to grow and cost the most.
Shop Freshwater Pearl Beads
Browse our pearl beads for every freshwater shape we carry, mother of pearl beads for pearly luster in cut and carved shapes, Griffin silk cord for knotting, and June birthstone beads. Then learn to knot pearls with silk cord, or read up on pearl jewelry care.
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