How to vet a lab-grown diamond manufacturer
Ten checks that separate a real grower from a website, the documents to ask for, and how to make your first order safe.
1–3. Is the company real?
Start with what you can check without the supplier's help.
- Registered name and number. Ask for the legal company name, registered address and registration number, then look it up in the official register. In India that is the Ministry of Corporate Affairs (MCA) company search; partnerships and proprietorships won't be there, so ask for their GST registration instead.
- Export licence and tax number. An Indian exporter needs an Import Export Code (IEC) from the DGFT, and most have a GSTIN you can check on the public GST portal. The name on both should match the name on the quote and the bank account.
- Trade body membership. If a supplier says it is a member of the Gem & Jewellery Export Promotion Council (GJEPC), the Responsible Jewellery Council (RJC) or any other body, find it in that body's own directory. A logo on a website proves nothing.
Lab logos (IGI, GIA and others) on a supplier's website are not company certifications. They only mean the supplier sends stones to those labs for grading. Check the individual reports instead (step 7).
4. Is there a factory?
Ask for a live video call inside the factory, at a time you choose. Ask the person to walk from the reactors or presses to the cutting floor without cutting the call. Ask how many reactors or presses are running today and what is growing in them. A pre-recorded film can be borrowed; a live call cannot.
If you can visit, do. Most Indian growers are in and around Surat, a short flight from Mumbai.
5–7. Are the stones what they say?
- Growth method per stone. The supplier should state whether each stone is CVD or HPHT. See CVD vs HPHT.
- Treatment disclosure. Many CVD diamonds are given an HPHT treatment after growth to improve their colour. That is normal, but it should be disclosed on the report and invoice.
- Report numbers you checked. For graded stones, take the report number and look it up yourself on the lab's own site: IGI report check or GIA report check. Compare the weight, measurements and the laser inscription on the girdle.
8–10. Is the deal safe?
- Written quote. Price, currency, quote validity, lead time, Incoterm and who pays insurance. Use our RFQ template so every supplier answers the same questions.
- Bank details on letterhead. The account must be in the company's own name. Confirm the details by phone on a number you found yourself. Treat any email that changes bank details as fraud until proven otherwise.
- A trial order. A good manufacturer will ship a small parcel first. Check every stone against its report on arrival before you place the large order.
Score a supplier
Run the 10 checks
Tick each check the supplier has passed. Nothing is sent anywhere.
Questions
What documents should a lab-grown diamond manufacturer give me?
Company registration, export licence (an IEC for Indian exporters), tax number (GSTIN in India), a written quote, a proforma invoice, bank details on letterhead and, for graded stones, the lab report numbers.
Are IGI or GIA logos a company certification?
No. IGI and GIA grade individual stones. A logo on a website means the supplier sends stones to that lab; it says nothing about the company itself. Check each report number on the lab's own website.
Should I pay a deposit to a new supplier?
Only after the company, factory and bank checks pass, and ideally on a small trial order first. Pay by bank wire to an account in the company's own name.
From the publisher
Run INTI through the same checks.
INTI Diamonds grows CVD and HPHT lab-grown diamonds in India: white goods, fancy colours and large stones. Ask us for anything on the checklist, including a live video call of the factory before you pay.
We publish this guide. We would rather win your order by passing the checks than by hiding them.