Certification is the part of wholesale buying that is most often misunderstood — and most often used as marketing rather than as evidence. Here is what each document is, and what it is not.

IGI reports

The International Gemological Institute grades both mined and lab grown stones and issues a numbered report for each. For lab grown diamonds, an IGI report typically states carat weight, measurements, colour and clarity grades, polish and symmetry, fluorescence, the growth method, and whether the stone has been treated after growth. The report number is inscribed on the stone's girdle.

What it does not tell you: nothing about the setting's metal content, nothing about the jewellery's manufacturing quality, and nothing about whether the stone you receive is the stone that was graded. That last point is the one buyers get wrong.

GRA cards

GRA (Gemological Research Association) documentation is common in the moissanite trade. It is typically a card or small report stating that the stone is moissanite, with a stated colour and clarity. It is inexpensive, which is why it can be applied to volume lines.

What it does not tell you: it is not a full grading report in the IGI or GIA sense, and it should not be presented to a consumer as equivalent to one. Treat GRA as a material statement, not a quality guarantee.

The five verification checks

Number match. Confirm the certificate number against the online lookup for that laboratory, and confirm the stated weight and measurements match your stone.
Inscription match. Ask for a photograph of the girdle inscription under magnification. The number on the stone must equal the number on the report.
Measurement match. Verify the millimetre dimensions with callipers, not a carat scale alone. A 1 ct stone with wrong dimensions is a substituted stone.
Parcel line match. On your packing list, every line should carry its certificate number. If certificates arrive in a bag detached from the stones, the whole parcel becomes unverifiable.
Supplier statement. Ask for written confirmation that the certificate belongs to the supplied stone, on company letterhead. This converts a vague assurance into a contractual position.

A certificate is evidence only when it is tied to a specific stone by number, photograph and measurement. Otherwise it is a brochure.

How certification changes your costing

Certification is a per-stone cost, so it behaves differently at different order sizes. For a wholesale programme, the sensible approach is to certify selectively:

certify every centre stone above 0.50 ct in bridal lines, where the customer will ask;
certify one stone per design in fashion lines and keep the rest uncertified to protect margin;
certify in batches, since laboratories price per stone and per submission size;
list the certificate number on your own invoice so your customer inherits the evidence trail.

What to put in your supplier agreement

Three clauses remove most certification disputes: stones must be supplied with the certificate number matching the physical inscription; any substitution voids the return window from the date of discovery rather than the date of delivery; and the supplier will reissue or repair documentation at its own cost if a laboratory lookup fails.

Next step

If you want a factory quotation rather than a retail estimate, send us your stone list, target quantities and market. Our trade desk replies within 12 working hours with tiered pricing, lead times and shipping options, and you can browse the wholesale collection or OEM/ODM service in the meantime.

What to put in your purchase specification

Before you place a wholesale order, write the specification down and make the factory confirm it in writing. Every dispute we see between a buyer and a supplier traces back to a vague or missing specification sheet. The following items are the ones that actually cause problems when they are left open:

Item	What to state
Stone grade	Colour and clarity range, plus the tolerance you will accept against the approved master sample (±1 grade is standard)
Metal and purity	Exact karat or silver fineness, alloy type, and whether white gold is nickel-free
Plating	Type (rhodium, 18K gold) and thickness in microns — a thin flash plating wears through in months
Dimensions	Band width, stone measurement, chain length, and the weight tolerance per piece
Setting method	Prong, bezel, channel or pavé — this single choice can double labour cost
Packing	Poly bag, box, pouch, tag, barcode label, and how many pieces per carton
Documents	Which certificates, and whether you need a material declaration or assay report

MOQ, lead time and payment terms

Our standard terms across the catalogue are straightforward, and they are the same terms we quote in writing rather than adjusting per enquiry:

MOQ — 10 pieces per design for stock specifications, 50 pieces for mixed-design lots. Custom development starts from 30 pieces per style in 925 silver and 10 pieces in gold.
Tiered pricing — list price to 49 pieces, about 8% off from 50 pieces, about 14% off from 200 pieces, and negotiated pricing above 500 pieces with reserved production capacity.
Lead time — 7–15 days for stock designs, 10–20 days for custom or certified production runs. Add 3–7 days for express transit to Europe and North America.
Payment — 30% deposit with the balance before shipment, by T/T, PayPal, Western Union or Alibaba Trade Assurance.
Samples — single samples ship at list price and the cost is credited against your first order above 200 pieces.
Quality guarantee — 30-day return window on stock items, and a written remanufacture-or-credit commitment if a parcel falls outside the approved tolerances.

Quality control: what happens before your parcel leaves

Buyers who have been burned before usually want to know exactly what inspection was performed. This is our standard sequence on every wholesale order, whether it is 20 pieces or 2,000:

Incoming stone grading. Every parcel is checked for colour, clarity and measurement against the order sheet before it enters the setting line. Rejected stones are pulled, not downgraded and used anyway.
In-process inspection. Setters check prong security, stone alignment and surface finish at each station rather than at the end of the line.
Final QC under 10× magnification. Polish, plating thickness, clasp and hinge function, and hallmark accuracy are verified piece by piece.
Cleaning, photographing, packing. Pieces are cleaned, photographed against your PO number, and packed in individual poly bags inside export cartons.
Document preparation. Commercial invoice, packing list, certificate copies and — where required — a material declaration stating that the stones are laboratory-grown.

You receive the photographs and the packing list before the parcel ships, so you can flag anything before it leaves rather than after it arrives.

Frequently asked questions

Can I mix metals and stone grades in one order?

Yes. You can combine 925 sterling silver, 10K, 14K and 18K gold in the same production run, and specify different colour and clarity grades per line. Every combination is confirmed on a single approval sheet before production starts, so there is no ambiguity about which line is which.

How consistent is grading across repeat orders?

Repeat orders are graded against the master sample kept on file under your account, which is why buyers who reorder regularly see far less variation than buyers who switch suppliers each season. Tolerances are written into the approval sheet, so a reorder cannot drift without your written agreement.

Do you provide photography for my online store?

Every catalogued design has front, three-quarter and macro imagery in sRGB at print resolution, named to match the SKU so the assets map straight into your product database. For orders above 200 pieces we photograph your private-label version at no additional cost.

What happens if the goods do not match the sample?

Send photographs and the SKU list within 14 days of delivery. If the deviation exceeds the tolerances on your approval sheet, we remake the affected pieces or issue a credit — this is covered by our written quality guarantee and applies to every order, not only the first one.

Related wholesale collections

Moissanite Supplier & Manufacturer — 210 ready designs, MOQ from 10 pcs.
Moissanite Rings — 222 ready designs, MOQ from 10 pcs.
Loose Moissanite Stones — 10 ready designs, MOQ from 10 pcs.

Authoritative References

For buyers who need to verify the technical and regulatory basis of this guide, the following independent institutions publish authoritative reference data:

eCFR Title 19 - U.S. Customs regulations for tariff classification and import documentation.
European Commission - EU customs, tariffs and trade compliance resources.