Colour & craft
Buying lab-grown melee: a practical specification guide for jewellers.
Order by dimensions, matching requirements and documented screening—not a loose description of small diamonds.
The short answer
- For a setting, millimetre sizes and tolerances matter alongside total carat weight.
- A parcel screening result is not the same as an individual full grading report for every stone.
- Agree matching, counting, documentation and replacement requirements before ordering.
In this guide
Specify what the workshop needs
“Small D / VS diamonds” is not a complete order. A jeweller needs a diameter or length-and-width range, cutting style, quantity, matching expectations and a clear laboratory-grown description. If the pieces must fit an existing design, obtain the workshop’s dimensional tolerances before asking for a quotation.
Separate a production requirement from a broad commercial grade range. Decide what variation the design can accept and what would stop setting. A parcel can meet a total weight target yet contain an unhelpful distribution of individual sizes. Your written brief should make the usable size bins clear.
| Field | What to agree |
|---|---|
| Material and origin | Laboratory-grown diamond, explicitly disclosed |
| Size | Millimetre range or exact target plus acceptable tolerance |
| Style | Round or named fancy shape and cutting style |
| Quantity | Pieces per size bin and total required |
| Quality | Agreed colour and clarity ranges; matching expectations |
| Evidence | Screening scope, parcel identity and available documentation |
| Commercial scope | Quote unit, currency, delivery, timing and discrepancy process |
Pieces, carats and price basis are different units
Confirm whether a quote is per piece, per carat or for the whole parcel. An illustrative parcel of 30 stones averaging 0.03 ct has an estimated total of 0.90 ct. It is not the same as 30 stones of 0.30 ct, which total 9.00 ct. Decimal placement is a production and pricing issue, not a minor formatting detail.
For a per-carat quotation, confirm the measured delivered parcel weight and any rounding convention. For a per-piece quotation, confirm the piece count and size specification. An estimated carat conversion from diameter should not silently replace the measured weight used on the final commercial document.
Ask what the screening actually establishes
IGI offers parcel sorting that includes screening for laboratory-grown diamonds and simulants. GIA also publishes a melee analysis service that separates different material and origin categories. These demonstrate that parcel screening is a distinct workflow; they do not mean that our advertised goods have automatically undergone a particular laboratory’s service.
Ask who performed any claimed examination, which stones or parcel it covered, what the result means and how the delivered parcel remains linked to that record. A reference photograph, laboratory logo or generic supplier statement is not documentation of the delivered lot. Clarify how stones requiring further analysis were handled.
Match the parcel to the design
For pavé work, decide whether the visible consistency needs to be tighter than a broad grade range. For channel or calibrated settings, agree dimensions and tolerances with the setter. For fancy-shaped accents, establish orientation and paired appearance in addition to size.
Where pairs or layouts are important, request a clearly identified arrangement image and an agreed selection standard. A photo can help document matching but should not be treated as an independent colour grade. Keep the manufacturing requirement attached to the order rather than relying on memory during repeat sourcing.
Plan the receiving check before production
At receipt, compare the lot identity, count, measured parcel weight, size bins and supplied documentation with the agreed order. Resolve discrepancies before stones are set or mixed with other workshop goods. Keep the delivery record and retain separation between lots where traceability matters.
Agree how missing, out-of-tolerance or visibly mismatched pieces will be handled, including any replenishment request. These are order-specific commercial terms; this guide does not invent a universal return rule or promise instant replacement stock. Your final quotation and applicable client-care terms must answer those questions.
Make the second order easier than the first
Create a repeat brief using the successful dimensions, ranges and observations from the first order. State which characteristics must remain consistent and whether several size bins may be shipped together. Reconfirm availability, timing and complete shipment costs each time; a previous parcel is useful reference evidence, not a guarantee of identical future goods.
Common questions
Does every melee stone need a separate full report?
Do not confuse individual grading reports with parcel sorting or screening. Agree the documentation appropriate to your order and ask exactly what has been tested.
Can I order only by total carat weight?
If the stones must fit a particular design, also specify size bins, cutting style, quantity and tolerances. Total weight alone does not establish fit.
Are public catalogue guides wholesale quotes?
No. Trade parcels need individual quotations for the exact scope, matching and delivery arrangement.
Sources & editorial method
Prepared with AI assistance and checked against the primary references linked below. Our comparisons, worked examples and buying checklists are editorial guidance, not independent laboratory tests or a professional appraisal. Actual stone details and order terms require separate confirmation.
- IGI: diamond parcel sorting and screening (opens in a new tab)
- GIA: melee analysis service (opens in a new tab)
Technical sources checked on 5 October 2026. Laboratory services and report formats may change; the current issuing laboratory’s record takes precedence.