Can I supply my own lab-grown stones to a factory, and what changes?

ZKZ Editorial TeamMain answer · Product & gemmology desk

Yes, many factories will set customer-supplied stones, but the terms change: you carry the cost of the stones, the factory will want written counts, size tolerances and a loss allowance, and responsibility for breakage, loss or mismatched stones has to be agreed in writing before anything is shipped.

What changes when you supply the stones

1. Ownership and risk. The stones stay yours, and so does the risk of loss during transit and while they are at the factory, unless the contract says otherwise.
2. Counting and receipt. The factory should count, weigh and photograph the stones on arrival, and both sides should sign the record.
3. Tolerances. Stones must match the setting, and the factory will state the allowed size variation. Stones outside the tolerance may not fit the mounting or may look uneven.
4. Breakage and loss. Agree an allowance and who pays when it is exceeded. Replacement stones for a matched set need to come from you.
5. Quality control. Stones that are chipped or off size may be rejected before setting, so check them first.
6. Lead time. The factory cannot finish until the stones arrive, and a late or incomplete delivery delays the order.
7. Paperwork. Shipping stones across a border needs correct customs documents and a clear description.

What to keep and send

• Reports and the stone numbers, matched to each lot.
• Girdle inscriptions, if any. GIA says its laboratory-grown reports carry a girdle inscription of "Laboratory-Grown" with the report number.
• A packing list with count, weight and sizes.

Disclosure does not change

Our advice A stone's origin must still be described correctly in your listing, whoever supplied it. The FTC Guides allow the word "cultured" for laboratory-created diamonds only with a clear and conspicuous disclosure that the product is not a mined stone (16 CFR 23.12(c)(3)), so plain wording such as "laboratory-grown" is the safest choice.

It depends Supplying stones can lower your cost per piece if you buy well. It can also add risk and effort if you lack the tracking systems.

Uncertain We have not seen a standard for loss allowances, so agree it with each factory.

Questions to ask the factory

1. Do you accept customer-supplied stones, and is there a minimum order?
2. What tolerances do you need?
3. How do you count and store stones?
4. What allowance do you apply, and what do you charge if it is exceeded?
5. How do you return unused stones?

Related reading: Custom Lab Grown Diamond Jewelry: A Step-by-Step Guide · Jewelry Production Tolerances Explained

Sources

• GIA, What if my diamond is already inscribed?
• 16 CFR 23.12, FTC Jewelry Guides: definition and misuse of the word "diamond"

Fact = stated by the cited source. Our advice = editorial recommendation. Uncertain / it depends = limits of what can be said in general.