How much does the lab-grown diamond for a tennis bracelet cost?

At Caratura's October 2026 prices, about $715 of melee for 48 stones at 3 mm (five 1-ct bags, $745), about $2,035 for 37 single stones at 4 mm ($55 each in the 0.19–0.29 ct band), and about $2,940–3,420 for 30 stones at 5 mm ($98–114 each). All DE colour, VS–VVS clarity.

How many stones does a full eternity band take?

In a US size 6 the stone run is about 55 mm, giving roughly 28 stones at 1.5 mm (about $77 of laboratory-grown melee), 22 at 2 mm ($131), 19 at 2.5 mm ($177) or 16 at 3 mm ($238). A half eternity is half those counts. Full eternity bands cannot be resized, so half eternities are often the safer commission.

How many stones are in a riviera necklace?

At 5 mm stones with a 15 mm clasp allowance: about 73 stones for 16 inches, 80 for 18 inches and 90 for 20 inches — single laboratory-grown stones at $98–114 each, roughly $7,200–8,300 for a 16-inch necklace. Graduated rivieras are counted band by band and added together.

Why does calibration matter more in a tennis bracelet than a halo?

In a line piece every stone is on display and sits between two neighbours, so a 0.1 mm difference reads as a step in the row and a proud stone catches on fabric. In a halo an oversize stone can be placed at the back. Line pieces need a stated tolerance — Caratura sorts each melee bag to ±0.1 mm, one size per bag, and films it before dispatch.

Do I have to buy whole bags for an eternity band?

Round melee is sold by the 1-carat bag, one size per bag, from $149. One bag covers a full eternity band with spares at 1.5 mm and 2 mm (about 65 and 30 stones per bag); at 2.5 mm and 3 mm (about 16 and 10 per bag) a full band takes two bags. What is left is matched stock for the next job, sorted to the same tolerance.

Eternity Band and Tennis Bracelet Stone Counts in Lab-Grown Diamond Melee — Sizes, Counts and Cost per Piece

Short answer: a 7-inch tennis bracelet takes about 48 stones at 3 mm (about $715 of laboratory-grown diamond melee at our prices), 37 at 4 mm or 30 at 5 mm; a full eternity band in a US size 6 takes about 22 stones at 2 mm (about $131); a 16-inch riviera necklace takes about 73 stones at 5 mm. All of it comes from one line: stones ≈ (run length in mm) ÷ (stone mm + 0.4 mm) — the 0.4 mm is the metal between settings. Counts, stone costs and how many 1-carat bags each piece needs are below.

The formula

Every stone in a line piece occupies its own diameter plus a sliver of metal on each side. That spacing — the pitch — runs about 0.3 mm in tight shared-prong work and 0.5 mm in a heavier four-prong link. Use 0.4 mm unless you know your setter's style.

stones ≈ (finished length − clasp allowance) ÷ (stone diameter + 0.4 mm)

Clasp allowance is 10–15 mm on a bracelet, 12–18 mm on a necklace. Round down: a line that comes up one stone short is finished with a slightly longer clasp; a line one stone over cannot be finished at all.

Tennis bracelet — 7 inch (177.8 mm), 165 mm stone run

Up to 3.6 mm the stones come from our round melee bags (1-ct bag price ÷ approximate count = per-stone cost); 4 mm and larger are our single round stones, priced by weight band. All DE colour, VS–VVS clarity, Hearts & Arrows cut.

7-inch tennis bracelet — stone counts and laboratory-grown diamond cost (prices as listed in October 2026)
Stone size	Approx. weight each	Stones	Approx. total weight	Sold as	Stones for the bracelet (approx.)
2 mm	0.033 ct	68–69	≈2.3 ct	Melee, 3 bags of 2.0 mm ($179 each)	$406 of stones; $537 for 3 bags with spares
2.5 mm	0.06 ct	56–57	≈3.5 ct	Melee, 4 bags of 2.5 mm ($149 each)	$521 of stones; $596 for 4 bags
3 mm	0.10 ct	48–49	≈5 ct	Melee, 5 bags of 3.0 mm ($149 each)	$715 of stones; $745 for 5 bags
3.5 mm	0.15 ct	42	≈6.4 ct	Melee, 6 bags of 3.5 mm ($149 each)	$894 for 6 bags
4 mm	0.25 ct	37	≈9 ct	Single stones, 0.19–0.29 ct band, $55 each	≈$2,035
4.5 mm	0.35 ct	33	≈12 ct	Single stones, 0.30–0.39 ct band, $76 each	≈$2,508
5 mm	0.45–0.50 ct	30	≈14 ct	Single stones, 0.40–0.49 or 0.50–0.59 ct band, $98–114 each	≈$2,940–3,420

For a 6.5-inch bracelet subtract about 3 stones at 3 mm, 2 at 5 mm; for 7.5 inch, add the same. Single stones are sold by weight band with the exact weight on the packet; for a line piece, say it is for a bracelet and we select stones close in diameter.

Eternity and half-eternity bands

Here the run length is the circumference the stones sit on, a little larger than the finger circumference because the stones ride on the outer face of the band. A workable figure is finger circumference + 3 mm. Costs are for the full count at our per-stone prices: 1.5 mm $2.75, 2 mm $5.97, 2.5 mm $9.31, 3 mm $14.90.

Full eternity band — stone count by ring size, with laboratory-grown diamond melee cost
Ring size (US)	Stone run	1.5 mm	2 mm	2.5 mm	3 mm
5	≈52 mm	27 · $74	21 · $125	17 · $158	15 · $224
6	≈55 mm	28 · $77	22 · $131	19 · $177	16 · $238
7	≈57 mm	30 · $83	23 · $137	19 · $177	16 · $238
8	≈60 mm	31 · $85	25 · $149	20 · $186	17 · $253

A half eternity is half these counts; a three-quarter is 75%. Half eternities are the safer commission — a full eternity cannot be resized, and the customer usually finds that out later. One 1-ct bag covers a full band with spares at 1.5 mm (about 65 stones per bag) and 2 mm (about 30); at 2.5 mm (about 16 per bag) and 3 mm (about 10) a full band takes two bags, and the remainder is matched stock.

Riviera necklaces

Same formula, longer run. At 5 mm with a 15 mm clasp allowance: 16 in (406 mm) → about 73 stones; 18 in (457 mm) → about 80; 20 in (508 mm) → about 90. In laboratory-grown diamond that is single stones from the 0.40–0.49 or 0.50–0.59 ct band at $98–114 each — roughly $7,200–8,300 of stones for a 16-inch riviera, which is the piece where the price gap to mined diamond is largest. A finer 16-inch riviera in 3 mm melee takes about 115 stones, 12 bags, about $1,800.

Graduated rivieras are counted section by section — count each size band separately and add the results. This is the one piece where ordering each size as a single bag matters most: 80 stones set side by side leave nowhere for a mismatch to hide.

Why calibration decides whether a line piece works

In a halo one oversize stone can be tucked at the back. In a line every stone is on display and adjacent to two neighbours, so a 0.1 mm difference reads as a step in the row, and a stone that sits proud catches on fabric. This is the setting type where a stated tolerance earns its money — every bag of our round melee is one size, sorted to ±0.1 mm of the stated size, guaranteed in writing, and filmed before dispatch. For stones above 3.6 mm, tell us the piece is a line piece: single stones are sold by weight band, and we select from the band for diameter so the row sets evenly.

How many to order

Add 10–15%, minimum two spares. A 48-stone bracelet is a 54-stone order. Round melee is sold by the 1-carat bag at $149–279 depending on size — a 5 ct tennis bracelet in 3 mm is five bags of 3.0 mm, with the spares already in the bags — and single stones from 0.19 to 0.99 ct are sold by the piece, so 37 stones at 4 mm is a normal order. There is no minimum beyond one bag or one stone.

Send the finished length, the stone size and the setting style, or a photo of the design, and we confirm the count and show you the actual stones before you pay. Message Leilei on WhatsApp.

Questions jewelers ask

How many stones are in a 7 inch tennis bracelet?: About 48 stones at 3 mm (≈5 ct total), 42 at 3.5 mm, 37 at 4 mm, or 30 at 5 mm. The formula is stones ≈ (finished length − clasp allowance) ÷ (stone diameter + 0.4 mm); a 7-inch bracelet has roughly a 165 mm stone run after a 10–15 mm clasp allowance.
How much does the lab-grown diamond for a tennis bracelet cost?: At Caratura's October 2026 prices, about $715 of melee for 48 stones at 3 mm (five 1-ct bags, $745), about $2,035 for 37 single stones at 4 mm ($55 each in the 0.19–0.29 ct band), and about $2,940–3,420 for 30 stones at 5 mm ($98–114 each). All DE colour, VS–VVS clarity.
How many stones does a full eternity band take?: In a US size 6 the stone run is about 55 mm, giving roughly 28 stones at 1.5 mm (about $77 of laboratory-grown melee), 22 at 2 mm ($131), 19 at 2.5 mm ($177) or 16 at 3 mm ($238). A half eternity is half those counts. Full eternity bands cannot be resized, so half eternities are often the safer commission.
How many stones are in a riviera necklace?: At 5 mm stones with a 15 mm clasp allowance: about 73 stones for 16 inches, 80 for 18 inches and 90 for 20 inches — single laboratory-grown stones at $98–114 each, roughly $7,200–8,300 for a 16-inch necklace. Graduated rivieras are counted band by band and added together.
Why does calibration matter more in a tennis bracelet than a halo?: In a line piece every stone is on display and sits between two neighbours, so a 0.1 mm difference reads as a step in the row and a proud stone catches on fabric. In a halo an oversize stone can be placed at the back. Line pieces need a stated tolerance — Caratura sorts each melee bag to ±0.1 mm, one size per bag, and films it before dispatch.
Do I have to buy whole bags for an eternity band?: Round melee is sold by the 1-carat bag, one size per bag, from $149. One bag covers a full eternity band with spares at 1.5 mm and 2 mm (about 65 and 30 stones per bag); at 2.5 mm and 3 mm (about 16 and 10 per bag) a full band takes two bags. What is left is matched stock for the next job, sorted to the same tolerance.

By Leilei, founder of Caratura — I source, inspect and pack every order myself. Every price is published on the product pages — no price list, no quote. Message me on WhatsApp with your spec for a stock check.