How to Verify an Overseas Gemstone Supplier (Before You Send Money)

Written by a supplier in China, about how to check suppliers in China. Read it with that bias in mind — then use every test below on us.

Buying loose stones from the other side of the world means paying a stranger before you can see what you bought. Most advice about this is either fear-mongering or marketing. What follows is the set of questions that actually separate a supplier who can deliver from one who can't — and, at the end, an honest list of the things we can't prove to you before you order.

First: what that certificate card actually is

Almost every parcel of moissanite out of Asia arrives with a card that looks like a lab report — most often a "GRA" card. Buyers read it as a quality guarantee. It isn't one, but it isn't meaningless either, and the difference matters.

What the card really carries is a size label. In practice these cards state the stone's dimensions and the corresponding diamond-equivalent weight (DEW) — the weight a diamond of that size would be. That is the trade convention for moissanite: sizes are expressed by reference to diamond so a jeweller can match a 6.5 mm stone to a 1 ct setting without doing conversions at the bench. Read that way, the card is a useful spec sheet.

Here is the consequence almost nobody explains. Moissanite has a lower specific gravity than diamond, so a moissanite cut to the size of a 1 ct diamond actually weighs less than the carat figure printed on the card — commonly cited as around 10%, though the real gap varies with shape and cut depth and can be wider. Put a "1 carat" moissanite on a scale and it will read meaningfully under 1 ct. That is physics, not a short-weight parcel. The same applies to melee sold by the carat bag: the stone count and the millimetre size are the numbers that matter, not the reading on your scale. Knowing this in advance saves an unnecessary dispute with an honest supplier.

What the card cannot tell you is quality. GRA is not an accredited gemmological laboratory in the sense buyers assume — the cards are produced in bulk on a layout closely modelled on GIA's, and they restate the parameters the seller supplied. No independent assessor examined your stone. In this trade, cut and clarity are set by the factory and by the price point you bought at — what you pay for is what gets made. A card cannot change that, and no card will tell you which grade you were sold.

And for melee, individual certification does not exist at all. IGI — which does issue genuine moissanite reports — covers stones from 0.50 to 5.00 carats. Melee runs roughly 0.005 to 0.10 ct per stone: two orders of magnitude below the smallest stone any laboratory will put on a report. A 1.5 mm accent stone weighs about 0.014 ct DEW; grading it individually would cost many times the stone. So a certificate accompanying a melee parcel is a size label at best.

None of this is an argument against buying moissanite from China — most of the world's moissanite is cut there. It is an argument for reading the card as a spec sheet, and testing the supplier for everything else.

Eight questions that actually tell you something

Send these before you send money. What matters is not just the answer — it's whether they answer at all.

1. "What tolerance do you hold, and will you put it in writing?"

Good answer: a number. "±0.1 mm of the stated size" is a normal, achievable commitment for calibrated melee. Bad answer: "very good quality, exact size, don't worry." A supplier who won't commit to a number in writing is telling you how their parcels get sorted: by eye, from a bin.

Us: ±0.1 mm, published on our calibration guarantee page, with a 14-day reporting window and free replacement or refund.

2. "Which grade am I buying — and what would the next grade up cost?"

Because quality is set by the factory and the price point rather than by any card, the honest way to find out what you're getting is to make the supplier price the alternatives. A supplier who works with real grades can quote you two or three of them. One who answers only "best quality, D VVS" to every question is quoting a slogan, not a specification.

3. "Will you film my actual stones before dispatch — with a gauge in frame?"

Pre-shipment video is standard now, which means the useful question is what's in the video. A glamour clip of sparkling stones on velvet proves nothing; it may not even be your parcel. Ask for the stones against a caliper, a sieve plate, or a ruler, and for the parcel label visible in the same shot. Anyone unwilling to spend two minutes on that for a paying order is telling you something.

Us: yes, and it's how we ship every order. Fair caveat below.

4. "Is this one cutting batch, or topped up from stock?"

This is the question almost nobody asks, and it explains most "the stones don't match" complaints. Bins get refilled from different cutting runs; individually every stone measures "2.0 mm", but the parcel spans 1.9–2.15 and the corners differ face-up. For any row work — pavé, channel, eternity — a single matched lot matters more than the nominal size. (Longer version: why melee doesn't match.)

5. "Can I buy one small parcel first?"

A supplier who requires 100 carats to start is a supplier you cannot test. The cheapest due diligence available is a real order, small, of the exact size you'd actually use — not a free "sample" (see below). If minimums make a trial impossible, the relationship is unverifiable no matter how good the answers sound.

Us: no minimum; a 1-carat calibrated bag is $28, and shipping is $20 flat worldwide, free over $100.

6. "How do you want to be paid?"

This is the single most predictive question, and it has nothing to do with gemmology. Card or PayPal means a dispute process exists. Bank wire, Western Union, USDT or "friends and family" means that once the money leaves, your only recourse is the supplier's goodwill. Plenty of honest factories prefer wire because it's cheaper for them — but if a new supplier insists on an irreversible method for a first small order, walk away.

7. "Who handles customs — and what happens if I'm charged?"

"Buyer is responsible for all import duties" is not a scam, but it means your quoted price is not your real price. Ask for the incoterm. DDP means duties are prepaid and the price you agreed is the price to your door. Ask, too, what happens in the destinations where prepayment isn't possible — a supplier who has thought about it will have an answer.

Us: DDP prepaid to nearly all destinations; where prepayment isn't available (Switzerland, for example) anything collected on delivery is refunded in full against the receipt. European buyers: what DDP covers in the EU, UK and Switzerland.

8. "What happens if a stone is out of tolerance — and by when do I have to tell you?"

A real policy has a deadline and a remedy, both written down before you buy. "We will solve any problem, please trust us" is not a policy; it's a mood. Vague goodwill is exactly what evaporates when there's an actual claim.

The sample trap

The classic failure mode is not fraud, it's selection. You ask for a sample; a human being picks the best five stones in the drawer; you approve; the production order is filled by scoop from the bin. Everyone behaved reasonably and the outcome is still wrong.

Two ways around it: buy a real parcel rather than a hand-picked sample, and when it arrives, measure ten stones at random — not the prettiest ten. Ten stones with a gauge tells you more than any certificate, video or reference ever will. Check the count against what the bag should hold, too — our size chart lists the stones per 1-carat bag at every size. What you should not do is judge by weight on a scale: as above, moissanite reads under its stated carat figure by design.

What we can't prove to you

Every test above, we pass — which is exactly why you should be suspicious of an article we wrote. So here is the other side, plainly:

• A pre-ship video is evidence, not proof. It shows stones with a gauge; it cannot prove those specific stones went in the envelope. Only your own gauge, after delivery, closes that gap. That's why our reporting window exists.
• We can't prove the tolerance claim before you buy. No supplier can. It is a promise until your first parcel makes it a fact.
• We are small and new, so we have very few reviews. A long trail of independent feedback is genuinely useful evidence, and we don't have one yet. Weigh that against us, not for us.
• We are one person, not a factory floor. That means direct answers and no minimums — and it also means we are not the right supplier for someone who needs 500 carats next week.

The five-minute checklist

1. Read the certificate card as a size label, not a quality grade — and never expect one for melee.
2. Get the tolerance number in writing.
3. Make them price two grades, so you know which one you're buying.
4. Require a pre-ship video with a gauge and the parcel label in frame.
5. Ask whether it's a single cutting batch.
6. Pay by a method that has a dispute process.
7. Confirm the incoterm — who pays duty.
8. Get the claim window and remedy in writing before you order.
9. Start small; measure ten random stones and count the bag — don't weigh it.

If a supplier clears all nine, the remaining risk is ordinary commercial risk — the same risk you carry with a domestic supplier. If they dodge three of them, no certificate in the box will save you.

Questions about a spec, ours or anyone else's? Message us on WhatsApp from any product page — we answer specification questions whether or not you ever buy from us. How we work, and what we stock: the wholesale page.

Frequently asked questions