Buyer's guide · Updated October 2026
Lab-grown diamond manufacturers: how to find one you can trust.
Most lab-grown diamonds are grown in India and China, and many pass through one or two traders before they reach you. This guide shows you how to reach the grower, check it is real, and write a request it can quote on.
Score a supplier
Tick what the supplier has actually shown you. Nothing leaves your browser.
The supply chain
Who you are actually buying from
Every step adds margin and distance from the facts about the stone. The closer you buy to the grower, the more you can verify.
The test: ask "did you grow this stone?" A grower can show you the reactor or press it came from. A trader will tell you where they bought it. Both answers are fine. Not knowing which one you are dealing with is the problem.
Start here
The guides
How to vet a manufacturer
Ten checks, the documents to ask for and the red flags that end a conversation.
Read → CountryManufacturers in India
Surat, Mumbai, how Indian growers sell, and how to check one from abroad.
Read → TechnicalCVD vs HPHT
What each method is good at, treatment disclosure and how to specify.
Read → ToolRFQ template
Fill in your requirement and copy a request any supplier can quote on.
Build one →Red flags
When to walk away
- Bank account in a different name from the company, or new bank details sent by email.
- "Largest grower" or "certified company" claims with nothing you can look up.
- Lab logos on the website but report numbers that don't check out on the lab's own site.
- Won't say whether a stone is CVD or HPHT, or whether it was treated.
- Factory tour only as a polished video; no live call.
- Prices far below everyone else's for the same specification.
Good signs
What a real grower shows you
- Registration, export and tax numbers you can check in public registers.
- A live video call on the growing floor, at a time you choose.
- Method and treatment stated per stone, on the invoice.
- A written quote with currency, validity, lead time and Incoterm.
- Happy to start with a small trial parcel.
- Says what it can't do, too.
By country
Buying from where you are
Hubs, labelling rules, customs points and time zones for buyers in the main markets.
India
Where most CVD diamonds are grown, and how to buy direct.
Read →USA
New York's Diamond District (47th Street) is the main trading hub.
Read →UAE
Dubai is the hub.
Read →UK
London's Hatton Garden is the traditional trade quarter; Birmingham's Jewellery Quarter is the manufacturing base..
Read →Hong Kong
Hong Kong is a free port and one of Asia's main diamond trading centres.
Read →Belgium (Antwerp)
Antwerp is Europe's diamond centre.
Read →Questions buyers ask
FAQ
Where are most lab-grown diamond manufacturers based?
Most gem-quality lab-grown diamonds are grown in India and China. India, centred on Surat in Gujarat, leads in CVD growing and in cutting and polishing. China leads in HPHT growing. The US, Europe, Singapore and others have smaller producers.
How do I know a lab-grown diamond manufacturer is real?
Look the company up in its government register, ask for its export licence and tax number, confirm any trade body membership in that body's own directory, check report numbers on the lab's website, and ask for a live video call inside the factory. A real manufacturer can do all of this in a day.
What is the difference between a manufacturer and a wholesaler?
A manufacturer grows rough diamonds, and often cuts them too. A wholesaler or trader buys from manufacturers and resells. Buying from the grower can be cheaper and gives you more control over the goods; a wholesaler can offer a wider mix and faster local delivery.
Do lab-grown diamonds need a Kimberley Process certificate?
No. The Kimberley Process covers rough natural diamonds. Lab-grown diamonds are declared under HS heading 7104 and must be clearly described as laboratory-grown on invoices.
Is CVD or HPHT better?
Neither is better in itself. Both produce real diamond. CVD leads in larger white stones and is often given a post-growth treatment to improve colour; HPHT is strong in small stones and some fancy colours. Specify what you need and ask the supplier to state the method for each stone.
How do I pay an overseas diamond manufacturer safely?
Use a bank wire to an account in the company's own name, confirmed on its letterhead and by phone. Start with a small trial order. Be wary of any request to pay a personal account or to switch bank details by email.
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.