Best Silk Cord for Pearls: Matching Size, Colour and Card to the Strand

A pearl strand is matched twice: once for the pearls, and once for the cord that carries them. The second match decides how the knots sit, how the strand drapes, and how long it lasts before it needs restringing. This guide sets out how to choose the best silk cord for pearls by drill hole, colour, and card, written for the bench jeweller and the shop that supplies them. GRIFFIN is a historic brand founded in 1866 that supplies high-quality Bead Stringing materials and accessories for jewellery making, and its silk has been the trade benchmark for pearl stringing for 160 years.

The drill hole decides the cord, not the pearl size

Two 8 mm pearls can carry quite different drill holes. Cultured saltwater pearls are usually drilled to a consistent size; freshwater pearls are often drilled finer, and the holes can vary from pearl to pearl within one strand. A cord chosen by pearl size alone either jams in a tight hole or sits loose in a wide one.

The rule is to choose the thickest GRIFFIN size that passes through the hole on its needle. That cord ties a knot large enough to sit on the edge of the hole rather than slip inside it.

The silk itself carries the rest of the standard. GRIFFIN 100% Natural Silk is filament silk from the centre of the cocoon thread, Triple Twisted, with the Needle Attached: Mastery since 1866, and in GRIFFIN's own words, The Best of the Best. For the full background on the line, see the Natural Silk bead cord guide.

Measuring a drill hole without a gauge

A hole gauge is useful, but the cord itself is the more reliable test. Take a spare pearl from the strand, or the pearl whose hole looks tightest, and thread the size you expect to use. The cord should pass with light resistance. Then tie a knot and press it against the hole. If the knot starts to sink in, go up a size; if the cord will not pass, go down one.

Check several pearls, because holes vary within one strand. Size the cord for the tightest hole, then check the knot against the widest. A bench that does regular pearl work saves time by keeping a test card in each of the common sizes, so every new strand can be fitted in a few minutes before the work starts.

The diameter table: 0.30 to 1.05 mm against bead type

GRIFFIN 100% Natural Silk runs from No. 0 to No. 16, and the diameter sets the job each size suits:

Sizes for 6 mm, 7 mm, 8 mm and 10 mm pearls in practice

For 6 mm pearls, start with No. 3 and test No. 2. Fine freshwater drilling often needs the smaller size; a well-drilled cultured strand usually takes No. 3.

At 7 mm, No. 4 is the usual starting point, with No. 3 for tight holes and No. 5 where the knot shows signs of slipping.

For 8 mm pearls, start with No. 6. Most strands settle between No. 5 and No. 7, and a size outside that band is a signal to look again at the drilling.

For 10 mm pearls, start with No. 8, moving to No. 10 when the hole is open enough to take it. Larger pearls carry more weight, so the thicker size is worth using wherever it passes.

The same logic applies to coral. Coral beads are often finely drilled for their size, so begin around No. 2 to No. 4 and test before settling on a size.

Why the cord should fill the hole rather than pass loosely through

A loose cord lets each pearl shift along the strand. Every movement works the edge of the drill hole against the cord, and the knot, which is small relative to the hole, can be drawn inside it. Over time the spacing goes and the strand starts to look tired.

A cord that fills the hole holds each pearl still between its two knots, and each knot sits firmly on the edge of the hole. The strand also drapes more evenly, because nothing can kink at a pearl that cannot move. This is the main reason the thickest size that passes is the right one.

Colour: matching cord to nacre, and when a contrast colour is deliberate

GRIFFIN 100% Natural Silk comes in 21 colours for both 10 and 5 pack: white, light pink, dark pink, coral, red, garnet, yellow, amber, blue, dark blue, lilac, amethyst, turquoise, jade green, green, olive, cornelian, beige, brown, grey, and black.

Cord shows in every knot and can show faintly through the nacre near the hole, so a matched colour lets the knots disappear. White suits white and cream pearls, light pink suits pearls with a rosé overtone, grey suits silver and grey pearls, and black suits dark and black pearls. For golden pearls, test beige and amber against the strand in daylight before choosing.

Contrast is a design decision. Coloured knots between white pearls turn each knot into a visible accent, a look that works in fashion pieces and in bracelets that sit beside other jewellery. When the brief is a classic strand, match the colour; when the brief is a statement, choose the knot colour as deliberately as the pearls.

Cultured, freshwater and baroque strands, and the fitting problems each brings

Cultured saltwater strands are the easiest to fit. The pearls are round and the drilling is usually even, so one size runs the whole strand.

Freshwater strands bring two problems: smaller holes and more variation between pearls. Size for the tightest hole, check the knot on the widest, and expect to work one or two sizes finer than a saltwater strand of the same pearl size.

Baroque pearls bring the opposite problem. Their shapes are irregular and their holes are often wide or angled, so the cord needs to be thicker. The 0.80 mm to 1.05 mm range exists for exactly this work, and a larger size lets the knot cover a hole that a finer cord would leave exposed.

When the strand needs High Performance

Some pearl pieces combine pearls with other materials, and the cord has to suit the hardest of them. Necklaces or bracelets using hard gemstones require GRIFFIN High Performance. The same applies to strands with heavy metal beads, or with holes so fine that silk at the size that passes would be too slight for the weight.

High Performance is white only and comes in 10 sizes from No. 0 to No. 10, covering 0.30 mm to 0.90 mm. It is triple twisted with the needle attached, 15 times stronger than steel by weight, and cannot be broken by hand even at the smallest diameters. The High Performance bead cord review covers the technical detail.

What to specify on a trade order, and the sizes a shop should hold

A clear order line names five things: the product line, the colour, the size number, the pack size, and the quantity. For example: 100% Natural Silk, white, No. 6, pack of 10, three packs. Cards come in packs of 5 or 10.

A shop with regular pearl customers can cover most work with a compact core stock:

• White in No. 2, No. 3, No. 4, No. 6, No. 8, and No. 10

• Light pink, grey, and black in No. 4, No. 6, and No. 8

• High Performance in No. 4 and No. 6 for strands that include hard gemstones

Order the remaining colours as customers ask for them. Because the silk is hand-dyed, order all the cards for one strand or set together. Larger stock orders above the published thresholds on the Discount page reduce the cost per card.

A size selection table for pearls

Go finer when the cord will not pass the tightest hole. Go thicker when the knot starts to sink into the widest one.

Conclusion

The best silk cord for a pearl strand is the one that fits its drill hole: the thickest GRIFFIN size that passes on its needle, tested against the tightest and widest holes in the strand. Colour follows the nacre for a classic strand and becomes a design decision when the knots are meant to show. Freshwater strands usually run finer, baroque strands thicker, and any piece that includes hard gemstones moves to High Performance. For a shop, a compact core of white, light pink, grey, and black in the middle sizes covers most pearl work, with the rest ordered as needed.