Melee Screening 101: How to Screen Melee for Lab-Grown Salting in Your Parcels

How to screen melee for lab-grown salting: run every small accent parcel through a diamond-type detection instrument that flags undisclosed CVD or HPHT lab-grown stones mixed into goods sold as natural. Melee is too small to grade individually, so it travels by parcel on trust. Screening replaces trust with verification, protecting you from a disclosure liability you never agreed to carry. Melee Screening 101: How to Screen Melee for Lab-Grown Salting in Your Parcels If you set pavé, halos, tennis bracelets, or eternity bands, you buy melee by the parcel, not the stone. That is exactly where the industry's quietest liability lives. A parcel sold to you as "natural melee" can contain a small percentage of undisclosed lab-grown diamonds, mixed in either by accident upstream or on purpose to lift margin. The trade word for it is "salting." When those stones reach your bench and then your customer's finger, the disclosure failure is now yours, regardless of where it originated. This guide explains how melee screening actually works, what a defensible buying process looks like, and why every parcel should arrive verified before it touches a setting. What Is Melee Salting and Why Does It Happen? Melee is the trade term for small accent diamonds, generally under roughly 0.18–0.20 ct (about under 3.8–4.0 mm). At that size, stones are not certified individually. They are sized on sieve plates, sorted by color and clarity range, and sold in parcels by weight. A single carat of 1.0 mm melee is roughly 200 stones. You are buying a population, not a SKU. "Salting" is the undisclosed mixing of lab-grown melee into a parcel represented and priced as natural. Because lab-grown melee can cost a fraction of comparable natural goods, even a small undisclosed percentage materially changes the parcel's true value. It happens for two reasons: Accidental contamination. Lab-grown and natural melee pass through the same cutting houses, sorting tables, and sieve plates. Cross-contamination upstream is real and often invisible to the seller. Deliberate fraud. A bad actor blends low-cost lab-grown into natural goods to widen margin, betting that nobody screens melee stone by stone. Either way, optical inspection cannot catch it. Lab-grown diamonds are real diamonds: same physical, chemical, and optical properties as mined diamond, produced by CVD (chemical vapor deposition) or HPHT (high pressure / high temperature) growth. A loupe, a microscope, or a moissanite tester will not separate them from natural at melee scale. The U.S. Federal Trade Commission requires that lab-grown origin be disclosed clearly in the trade, which means the disclosure obligation follows the goods to whoever sells them last — you. How Do You Screen Melee for Lab-Grown Salting? Melee screening is done with diamond-type detection instruments — automated machines built specifically to separate natural diamond from lab-grown and simulants at small sizes. They do not grade the 4Cs. They answer one question per stone: natural, or refer for further testing. The workflow looks like this: Bulk feed. The parcel is loaded into an automated screener that feeds melee through optical and spectroscopic analysis, often hundreds of stones per minute on the faster units. Type separation. The instrument distinguishes diamond type using ultraviolet absorption and luminescence signatures. Type IIa and certain spectroscopic signatures are characteristic of much CVD and HPHT lab-grown material. Pass vs. refer. Stones that read clean as natural pass. Stones with signatures consistent with lab-grown — or that the machine cannot clear — are kicked to a "refer" lane for a gemologist's secondary analysis on bench instruments. Documentation. A defensible process records the screening result for the parcel: instrument used, date, operator, pass rate, and disposition of referred stones. The key idea: screening is a type-detection step, not a grading step. It is designed to catch salting at the population level, fast, before the parcel is ever sold or set. What Instruments Are Actually Used? The major laboratories build and operate this category of equipment, and the technology is well documented by the Gemological Institute of America and the International Gemological Institute. For your purposes as a buyer, you do not need to own a screener. You need to confirm your supplier runs one and will stand behind the result in writing. A supplier who screens at the parcel level and documents it has converted "trust me" into "here is the record." Do Melee Diamonds Come Certified? Not individually, and you should be skeptical of anyone who implies otherwise. A 1.0 mm stone at roughly 0.005 ct cannot carry a meaningful per-stone certificate or laser inscription. So when a jeweler asks "do melee diamonds come certified," the honest trade answer is: Larger melee and pointers — toward the top of the size range, particularly Pointers (stones described by their point weight) — can sometimes be sold with grading documentation, especially when they cross into the smaller "single stone" territory. True small melee travels by parcel-level documentation: a sieve-graded color/clarity range, a stated origin (natural or lab-grown), and — critically — a screening record. That parcel-level record is the certificate that matters for melee. It is what lets you tell a customer, truthfully, that the accent stones in their piece were screened and verified to origin. The distinction between certification and screening is worth internalizing: a per-stone cert proves a single stone's grade; a screening record proves an entire parcel's origin. For melee, the second is the one that protects you. Single-Cut vs. Full-Cut, and the Mm-to-Carat Reality To buy melee defensibly you also need to speak its dimensional language, because tolerance and size are how parcels are described and matched. Melee comes single-cut (17–18 facets) or full-cut (57–58 facets), is sorted into trade tiers — Stars, Fulls, Pointers — and is sized on sieve plates. Calibrated melee for channel-set and pavé work holds a tolerance of roughly ±0.05 to 0.10 mm. Here is the canonical round-brilliant size reference the trade works from: Diameter (mm) Approx. carat weight Trade note 0.8 0.0025 ct Micro-pavé 1.0 0.005 ct ~200 stones per carat 1.25 0.01 ct Common pavé 1.5 0.015 ct Pavé / halo 1.75 0.02 ct Halo / accent 2.0 0.03 ct Accent 2.5 0.06 ct Side stones 2.75 0.08 ct Larger accent 3.0 0.10 ct Pointer territory 3.25 0.13 ct Pointer 3.5 0.17 ct Upper melee 3.8 0.20 ct Melee / small-stone boundary Why this matters for screening: the smaller the stone, the more of them in a parcel, and the more places a salted stone can hide. A salted percentage that looks trivial by weight can be a meaningful headcount of undisclosed stones across a micro-pavé order. Screening at the parcel level is the only practical way to clear a population that large. For the full sizing and sieve breakdown, see our companion guide on the melee size chart from mm to carat to sieve, and for tolerance specifics by application, calibrated melee for pavé, tennis, and eternity. What's the Real Cost of an Unscreened Parcel? Run the liability, not just the price. If an unscreened "natural" parcel turns out to be salted, you absorb several distinct costs: Disclosure exposure. You sold or represented goods inaccurately, even unknowingly. Under FTC guidance, lab-grown origin must be disclosed; the obligation does not care that you were the victim of upstream salting. Rework and recall. If a piece is already set or sold, correcting it means unsetting, replacing, re-screening, and re-delivering — on your dime and your reputation. Margin erosion you can't see. You paid natural prices for lab-grown stones. The fraud taxes you whether or not it is ever discovered. Relationship damage. A retailer who learns their "natural" pavé contained undisclosed lab-grown rarely gives a second chance. The math favors screening every time. The cost of verification is a rounding error against the cost of a single salted parcel reaching a customer. This is the same diligence logic that should govern who you buy from in the first place — see our checklist on how to vet a wholesale diamond supplier before your first memo. How Guru Diam Screens Every Melee Parcel At Guru Diam, melee origin is not a claim — it is a verified record. Our natural and lab-grown melee run on separate, clearly labeled tracks so the two populations never commingle on our floor. Natural parcels are screened with diamond-type detection before they are offered to trade partners, and referred stones go to gemologist review rather than back into the parcel. You receive parcel-level documentation that states origin, sieve-graded specs, and screening, so your own disclosure to the customer rests on verification rather than assumption. This sits inside the way we already run inventory: 11,000+ IGI and GIA certified stones live, with real-time online inventory and API/CSV feed tools so trade partners can pull current stock and specs into their own systems. For melee specifically, that means you can source 100% screened parcels of calibrated round melee and Pointers with the origin question already answered. Our dual natural and lab-grown track is a feature, not a risk — because the two are kept deliberately, auditably apart. When you also need fancy color accents, the same discipline applies; see fancy color melee sourcing. Open a Verified Wholesale Account Melee is the highest-volume, highest-trust line on your bench. Source it from a supplier who screens before you set. Open a verified wholesale trade account at /signup and book a working session with a specialist at /book-appointment to walk a screened parcel in person at our New York or Los Angeles desks. Natural and lab-grown, certified stones, calibrated melee, custom — All Under One Roof. Frequently Asked Questions What is lab-grown salting in melee parcels? Salting is the undisclosed mixing of lab-grown melee into a parcel sold and priced as natural. It happens both accidentally, through cross-contamination at shared cutting and sorting facilities, and deliberately, to widen margin. Because lab-grown diamonds share the same optical and physical properties as natural, salting cannot be detected by eye or loupe and requires diamond-type detection instruments to catch. How do you screen melee for lab-grown salting? You run the parcel through an automated diamond-type detection instrument that analyzes each stone's ultraviolet absorption and luminescence signatures, separating likely natural stones from those consistent with CVD or HPHT lab-grown growth. Stones that pass are cleared; stones the machine refers go to a gemologist for secondary analysis. The result is documented at the parcel level rather than stone by stone. Do melee diamonds come certified? True small melee is not certified individually — a 1.0 mm stone at about 0.005 ct cannot carry a meaningful per-stone report or inscription. Melee instead travels with parcel-level documentation: a sieve-graded color and clarity range, a stated origin, and a screening record. Larger melee and Pointers near the small-stone boundary can sometimes carry grading documentation. Why can't I just inspect melee with a loupe or diamond tester? Because lab-grown diamonds are real diamonds with identical physical, chemical, and optical properties to mined diamonds. A loupe, microscope, or standard diamond tester confirms a stone is diamond but cannot tell you whether it grew in the earth or in a reactor. Only diamond-type detection instruments separate natural from lab-grown at melee scale. What does a 100% screened melee parcel actually guarantee? It guarantees that every stone in the parcel passed type detection for the stated origin, or was referred and removed, and that the result is documented. It does not assign a 4Cs grade to each stone; melee is graded as a population by sieve and color/clarity range. The screening record is what lets you disclose origin to your own customer with confidence rather than assumption. Who is liable if a salted stone reaches my customer? Disclosure liability follows the goods to whoever sells them last. Under FTC guidance, lab-grown origin must be disclosed clearly, and being an unknowing victim of upstream salting does not remove that obligation. This is precisely why buying from a supplier who screens and documents every parcel transfers the verification burden off your bench.