The Melee Diamond Size Chart MM to Carat to Sieve, with Calibration Tolerances

The Melee Diamond Size Chart MM to Carat to Sieve, with Calibration Tolerances A melee diamond size chart mm to carat is the conversion reference every buyer needs before placing a parcel order: it maps a stone's millimeter diameter to its approximate carat weight and to the sieve plate that screens it. For round-brilliant melee, 1.0 mm runs about 0.005 ct, 2.0 mm about 0.03 ct, and 3.0 mm about 0.10 ct. Bookmark the table below. If you set pavé, build halos, run tennis lines, or assemble eternity bands, you order melee by the parcel and you live or die by calibration. Get the millimeter wrong by a tenth and the goods seat high, rock in the bezel, or refuse to drop into a channel. This is the working reference our New York and Los Angeles desks hand to trade partners so a melee order ships right the first time. Use it operator-to-operator: spec the mm, confirm the weight expectation, and lock the tolerance before money moves. What counts as melee, and where does the size range stop? In the trade, melee means the small accent diamonds that surround or accompany a center stone — pavé, halos, side rows, tennis links, eternity channels. The practical ceiling is roughly 0.18–0.20 ct, which corresponds to about 3.8–4.0 mm in a round brilliant. Above that you are into "pointer" goods talked about by individual weight rather than parcel; below it, you are buying by size and screening through sieves. Melee is the highest-frequency SKU on most benches because almost every mounting consumes it. That also makes it the line item most exposed to sloppy spec. A parcel that grades beautifully but runs +0.10 mm oversize against your seats is a rework problem disguised as a good buy. The size chart exists to take that variable off the table. The master melee size chart: mm to carat to sieve Here is the canonical round-brilliant reference. These mm-to-carat figures are the working numbers our desks quote against — use them to convert a design's millimeter callout into the parcel weight you should expect, and to anticipate stone count per carat. Diameter (mm) Approx. weight (ct) Trade size class Stones per carat (approx.) 0.8 mm 0.0025 ct Star / fine melee ~400 1.0 mm 0.005 ct Star ~200 1.25 mm 0.01 ct Star / 1-pointer ~100 1.5 mm 0.015 ct Full ~67 1.75 mm 0.02 ct Full / 2-pointer ~50 2.0 mm 0.03 ct Full / 3-pointer ~33 2.5 mm 0.06 ct Pointer ~17 2.75 mm 0.08 ct Pointer ~12.5 3.0 mm 0.10 ct Pointer (10-pt) ~10 3.25 mm 0.13 ct Pointer (13-pt) ~7.7 3.5 mm 0.17 ct Pointer (17-pt) ~5.9 3.8 mm 0.20 ct Top of melee range ~5 The stones-per-carat column is the one that saves you on costing. At 1.0 mm (0.005 ct), roughly 200 stones make one carat — so a 0.5-carat pavé build at that size is about 100 stones, and your per-stone setting labor, not the diamond cost, usually dominates. Read the chart in both directions: from a CAD millimeter callout to expected parcel weight, and from a target carat-weight-on-mounting back to stone count and setting time. How do Stars, Fulls, and Pointers actually divide up? These are parcel-floor terms, not lab grades, and usage varies slightly desk to desk — so confirm the mm with your supplier rather than trusting the word alone. As a working frame: Stars — the smallest melee, roughly under ~1.25 mm (under about a point each). Used for fine micro-pavé and fill work where stones read as sparkle, not individual diamonds. Fulls — the mid band, roughly 1.5–2.0 mm. The workhorse range for halos and shared-prong rows. Pointers — sold and discussed by their point weight: a "3-pointer" is ~0.03 ct (≈2.0 mm), a "10-pointer" is ~0.10 ct (≈3.0 mm), a "17-pointer" is ~0.17 ct (≈3.5 mm). Once a stone has a meaningful individual weight, the trade names it by points rather than lumping it as "full." When you spec a job, lead with the millimeter because that is what the seat is cut for. Let the point/Star/Full label follow. Our round melee and pointers category is organized this way so you can shop the mm first. How does sieving work, and how tight is calibrated melee? Loose melee is sorted into size bands by sieve plates — graduated round-hole plates stacked so stones drop through openings until caught at the band that matches their diameter. That is how a parcel marked "1.50–1.55 mm" gets its consistency. The full mechanics of plate sizing and band assignment are covered in our companion piece on calibrated melee for pavé, tennis, and eternity work; here, the figure to memorize is the tolerance. Calibrated melee tolerance is typically ±0.05 to 0.10 mm. That window is the difference between a parcel that drops cleanly into precut seats and one that fights you on the bench. For channel-set and shared-prong work — eternity bands especially — push for the tight end (±0.05 mm), because in a continuous line a single oversize stone telegraphs as an uneven gap. Setting type Recommended calibration tolerance Why it matters Micro-pavé / Stars ±0.05 mm Bead seats are tiny; oversize stones sit high and snag Halo / shared-prong ±0.05–0.10 mm Even spacing reads at a glance under magnification Channel / eternity ±0.05 mm One out-of-spec stone disrupts the entire continuous line Scattered accents ±0.10 mm Independent seats forgive minor variance Specifying a tolerance up front is the single cheapest way to prevent rework. A parcel quoted only as "1.5 mm" without a tolerance is an open invitation to receive goods anywhere from 1.45 to 1.60 mm. Single-cut vs full-cut melee: which faceting should you order? Two faceting standards live inside the melee range: Single-cut melee carries 17–18 facets. Historically common in the smallest sizes and in vintage repair, it shows broader, calmer flashes. It can be the right call when matching antique pieces or when a stone is so small that full faceting adds cost without visible return. Full-cut melee carries the standard 57–58 facets, the same architecture as a full-size round brilliant, and delivers the fine scintillation modern retail expects. For most contemporary mountings, order full-cut. Reserve single-cut for restoration matching or deliberate vintage looks — and when you are working antique-cut centers, coordinate the accent stones the same way you would coordinate cuts in our antique-cut sourcing guide. How do you keep lab-grown out of a natural melee parcel? If you carry a natural melee line, the contamination risk to manage is "salting" — undisclosed lab-grown stones mixed into a parcel sold as natural. Because melee is screened by size, not individually certified, salting is hard to catch by eye and is an accurate-disclosure and trust problem before it is a cost problem. The defense is diamond-type detection instrumentation that screens parcels at scale. This is a sourcing-discipline issue more than a chart issue, so we treat it in full in Melee Screening 101: how to avoid lab-grown salting. The short version: buy from suppliers who screen and disclose, and screen again on intake. For trade context on disclosure expectations, the Federal Trade Commission jewelry guidance and the grading framework published by GIA set the baseline both labs and buyers work from. Lab-grown melee: same chart, different sourcing math The mm-to-carat conversions above apply identically to lab-grown melee — a 1.0 mm stone is ~0.005 ct whether it grew by CVD or HPHT or came out of the ground, because lab-grown shares the same physical, chemical, and optical properties as mined diamond. What changes is the certification posture and the cost structure. For lab-grown melee, IGI is the practical trade default; IGI grades the large majority of lab-grown diamonds, and the International Gemological Institute report is what most parcels reference. Note that melee is generally bought against size and a stated quality range rather than individual stone certs — the cert conversation matters most as you move up into pointer and center goods. Where buyers do compare reports, hold to one rule: compare reports from the same lab, since a stone can grade up to about one color grade differently between labs. Frequently Asked Questions How many melee diamonds make one carat? It depends entirely on size. At 1.0 mm (about 0.005 ct each), roughly 200 stones make one carat. At 2.0 mm (about 0.03 ct), it is roughly 33 stones, and at 3.0 mm (about 0.10 ct), about 10 stones. Always convert from the millimeter your mounting calls for, not from a generic average. What is the largest size still considered melee? The practical ceiling is roughly 0.18–0.20 ct, which is about 3.8–4.0 mm in a round brilliant. Above that, stones are usually bought and discussed by individual weight as pointers rather than sorted by parcel. What calibration tolerance should I ask for? Calibrated melee typically runs ±0.05 to 0.10 mm. For micro-pavé, channel, and eternity work, specify the tight end (±0.05 mm); scattered independent accents tolerate ±0.10 mm. Always state a tolerance with your millimeter — a size callout without one invites out-of-spec goods. What is the difference between single-cut and full-cut melee? Single-cut melee has 17–18 facets and a calmer, broader flash, often used in the smallest sizes or for vintage matching. Full-cut melee has the standard 57–58 facets, matching a full round brilliant, and is what most modern retail mountings call for. What do Stars, Fulls, and Pointers mean? They are trade parcel terms. Stars are the smallest melee (roughly under ~1.25 mm); Fulls are the mid band (roughly 1.5–2.0 mm); Pointers are larger melee named by point weight (a 10-pointer is ~0.10 ct, ~3.0 mm). Usage varies by desk, so always confirm the actual millimeter. Should I order natural or lab-grown melee? Both convert on the same mm-to-carat chart. Lab-grown melee (CVD or HPHT) typically lowers your accent-stone cost and references IGI grading. If you run a natural line, screen incoming parcels for salting with diamond-type detection. Many partners stock both tracks to fit the mounting and the price point. Order melee that drops in clean — All Under One Roof Spec it once, ship it right. Guru Diam holds 11,000+ IGI and GIA certified stones across our New York and Los Angeles desks, with calibrated round melee and pointers, fancy color accents, and matched goods on real-time inventory — natural and lab-grown, All Under One Roof. Open a verified wholesale account at /signup Book a parcel review at our NY or LA desk at /book-appointment Bookmark this chart, then send us the millimeter and tolerance — we will quote against these exact numbers. For fancy accents, see fancy color melee sourcing.