A buyer in Dallas ordered a seven-inch tennis bracelet with 4.0 mm moissanite every 5.5 mm. On the desk it looked even. On the wrist the links rotated, half the stones tilted, and the row read as a chain with occasional dark gaps. The stones were fine; the spacing and the setting cup were wrong for wrist movement. A custom moissanite bracelet that goes dark on the wrist has a geometry problem, not a stone-quality problem, and spacing is the first number we check.
Below are the four spacing and cup numbers we spec on every tennis bracelet, with the link gauge and stone tilt behaviour we measure before the first link is cast.
The centre-to-centre gap
On a 4.0 mm stone we space links 5.0 to 5.2 mm centre-to-centre. That leaves a 1.0 to 1.2 mm metal web between stones, wide enough for the link to articulate without the stones kissing. Spacing tighter than 4.8 mm makes the stones rub and chip the girdles as the wrist flexes; spacing wider than 5.5 mm reads as a chain, not a bracelet. The exact gap depends on wrist size, because a seven-inch wrist flexes more than a six-inch. Our link spacing and gauge write-up holds the gap table per stone size.
The setting cup depth: keeping stones upright
The desktop-pretty bracelet failed because the setting cup was shallow. We build tennis cups to two-thirds of the stone's girdle depth on a 4.0 mm stone, so the stone sits fixed and does not rock in the seat. A shallow cup lets the stone tilt as the link turns, which sends light out sideways. The cup wall runs 0.5 mm with four prongs per stone. On bracelets above 5 mm stones we step to six prongs because the larger girdle needs more grip. Our tennis bracelet design overview shows the cup cross-section.
Link gauge and wrist flex
The link has to bend with the wrist without flipping the stone. We build tennis links in 1.1 mm wire for stones up to 4.5 mm, stepping to 1.3 mm above that. A stiffer link reads structural but does not lie on the wrist; a floppy link rotates the stones. The bracelet should flex to a C-shape when held at one end, not stay straight and not collapse. Bracelet clasp and link type are covered in our tennis and link bracelet overview.
Even light play around the curve
Light play on a tennis bracelet depends on every stone facing the same direction. As the wrist turns, outer-row stones catch light and inner-row stones go dark, which is normal. The mistake is making the cup angles uniform on a flat chain; on a curved wrist the stones on the outer arc need a slightly shallower tilt to face up. We set the cups on a wrist mandrel, not a flat jig, so the row reads even on the arm. Moissanite's doubled refraction, noted in the moissanite entry, means even small tilts read more visibly than on diamond, so cup angle matters more on this stone.
What gap suits a 4.0 mm tennis stone?
5.0 to 5.2 mm centre-to-centre, leaving a 1.0 mm web. Tighter and the girdles rub; wider and the row reads as a chain.
Why does my bracelet go dark on the wrist?
Usually a shallow setting cup that lets the stone rock. We set cups to two-thirds girdle depth on a wrist mandrel, not a flat jig.
How many prongs per tennis stone?
Four prongs up to 4.5 mm stones, six above. The larger girdle needs more grip to stay upright as the wrist flexes.
What link gauge keeps the row flexible?
1.1 mm wire to 4.5 mm stones, 1.3 mm above. The bracelet should flex to a C when held at one end.
The clasp and the safety chain
A tennis bracelet fails at the clasp more often than at the stones. We build the clasp in a figure-8 safety with a second latch, because a single-latch clasp opens if the band catches on a sleeve. The clasp length runs 15 mm on a seven-inch bracelet, and we add a short safety chain across the clasp so a lost latch does not drop the bracelet. Buyers who have had bracelets returned for a broken clasp should read our tennis and link bracelet overview, which lists the latch types we stock. The clasp weight is part of the balance: a heavy clasp on a light band pulls the bracelet around the wrist to one side. We match clasp weight to stone weight so the row sits centered on the arm. On a 4.0 mm stone row, a 2.5 g clasp balances; above that we step to a wider clasp.
Send us wrist size, stone size and the metal you stock. We return centre-to-centre gap, cup depth and link gauge on the CAD before the first link is cast. Ask us to spec your next custom moissanite tennis bracelet.
Frequently Asked Questions
Is moissanite a good diamond alternative for retail buyers?
Yes for price-sensitive customers who want brilliance and hardness. Moissanite ranks 9.25 on the Mohs scale, holds up to daily wear and costs a fraction of a natural diamond of the same size, so it resells fast in bridal and fashion lines.
What is the minimum order for wholesale moissanite?
MOQ starts at 50 pieces per design for stock items. Custom cuts and private-label settings usually start at 100–300 pieces depending on the mold.
Do you provide certificates with moissanite stones?
Yes. Every parcel ships with GRA or IGI documentation listing carat weight, color grade and cut. We recommend passing the certificate to your end customer for trust.
How long does sample and bulk production take?
Samples ship in 3–5 days. Bulk runs take 15–20 days under 500 pieces, and 25–30 days for custom work.
