Buying diamonds in Antwerp: how the rough-to-polished trade works
Why so much of the world's diamond trade still passes through a few streets in Antwerp, and how a buyer should prepare before walking into it.
A diamond's path from mine to counter is long, and most of it happens out of sight. Rough is sorted, valued, sold, planned, cut, polished, graded and sold again, often in different countries. A surprising share of that journey, for rough and polished alike, passes through a few streets beside Antwerp Central Station. For a buyer, understanding why is the most useful preparation there is.
Antwerp has traded diamonds for more than five centuries. The city's cutters were working stones in the fifteenth century, and the trade has survived wars, the rise of cutting in India and the relocation of the big rough sales to Africa. What remains is a concentration of dealers, bourses, laboratories, banks, customs and logistics that is very hard to reproduce elsewhere.
Why the trade stays in one square mile
The diamond district around Hoveniersstraat, Schupstraat and Rijfstraat holds several bourses, including one devoted to rough. Rough and polished goods cross the counters of the same few blocks, and a dealer can walk a parcel from a buyer's office to a grading lab to a courier without leaving the district. That density is the point. Diamonds are priced stone by stone and parcel by parcel, and a market works best when buyers and sellers can see the goods, compare them and settle quickly.
Belgium also built the administrative machinery around the trade. Rough entering or leaving the country is inspected and must travel with a Kimberley Process certificate, and polished shipments pass through a dedicated customs office for diamonds. For a buyer this matters less as history than as practice: goods bought here generally come with the paperwork that later buyers, insurers and banks will ask to see.
Rough and polished are two different skills
Buying rough is buying a forecast. The value of a rough stone depends on what it will yield once planned and cut: how much weight survives, where the inclusions fall, what colour and clarity the finished stones are likely to grade. Manufacturers scan rough and model the yield before they bid, and they still carry the risk that a stone reveals something inside once cutting begins. Unless you run or work closely with a cutting operation, rough is not a place to learn on the job.
Polished is where most retail and wholesale buyers belong. Here the questions are the familiar ones: the grading report, whether it matches the stone, the make, the fluorescence, and how the price compares with similar goods on neighbouring stands. Lab-grown diamonds add one more question to every conversation. They are a legitimate product with their own market and their own price level, and they must be disclosed as such. A reputable seller will show the report and, for melee and parcels, will be able to say how the goods were screened.
Preparing before you travel
The Antwerp trade runs on trust built over years, and a first-time buyer is a stranger to it. Preparation closes that gap faster than anything said at the stand. Expect to be asked for company documents before a serious purchase, because dealers and banks operate under anti-money-laundering rules and must know who they are selling to. Sanctions on Russian-origin diamonds mean origin questions now run in both directions, so be ready to ask about provenance and to answer questions about your own supply chain.
- Company registration, trade references and identification for everyone who will sign an invoice.
- A clear brief: shapes, sizes, colour and clarity ranges, natural or lab-grown, and a budget per carat.
- Agreed payment method in advance, usually a bank transfer in US dollars, which is how most diamonds are priced.
- Shipping and insurance arranged before you buy, so goods travel by secured courier rather than in a pocket.
- Your own loupe and tweezers, and a note of which laboratories' reports you will accept.
Memo is common between established dealers, where goods are taken on approval and returned or paid for within an agreed period. Do not expect it on a first meeting, and do not treat a verbal understanding as the terms. Whatever is agreed about returns, reports and payment belongs on the invoice or the memo itself.
In a trade that still closes deals on a handshake, the buyer who arrives with paperwork in order is the one who gets shown the better goods.
Valumira's eighth show is in Antwerp, 11 to 13 June 2027, at Antwerp Expo, with diamonds as its focus: rough, polished and lab-grown on separate floors. Friday is the trade day, and Saturday and Sunday are open to the public. Buyers who want to see rough should plan the Friday around it and leave the polished floors for the afternoon, when comparisons are fresher. Official stays for the show are arranged by Bookend Partners.