What the certification scheme is, why Sierra Leone sits at the heart of its history, how a certificate is issued and read, and how to be sure the rough you buy is genuinely conflict-free. Written from Freetown, updated October 2026.
The Kimberley Process Certification Scheme — KPCS, usually just "the Kimberley Process" — is an international agreement that governs how rough diamonds move between countries. Its rule is simple to state: a rough diamond may only cross a border if it travels in a sealed, tamper-resistant container, accompanied by a uniquely numbered certificate issued by the government of the exporting country, confirming that the stones are conflict-free. Countries that join the scheme may trade rough with one another; they may not legally trade rough with any country that has not joined.
Launched in 2003, the scheme now covers the overwhelming majority of the world's rough diamond production. It is not a quality grade and it is not about a diamond's colour or clarity. It is a provenance control — a system designed to answer one question at every border: did the money from these stones fund a war? For a buyer, the certificate is the document that answers it.
The Kimberley Process was born out of the wars of the late 1990s, and Sierra Leone is not a footnote in that story — it is close to the centre of it. During the country's civil war, rebel forces financed their campaign by seizing alluvial diamond fields and selling the rough into world markets, where it was indistinguishable from any other stone. The term "blood diamond" entered the language largely because of what happened here. The international response — a certification scheme that made origin legible and auditable — was in no small part a response to Sierra Leone.
That history is why Sierra Leone's participation carries particular weight. A country that lived through diamond-financed conflict, and then helped build and now operates the system designed to prevent it, is exporting rough with a credibility that a certificate alone cannot fully convey. When you buy certified rough from Sierra Leone, you are buying from the channel the scheme was, in part, written for.
"Conflict-free" is not a marketing adjective here — it is a documented status, tied to a numbered government certificate and a sealed parcel. The whole point of the scheme is that you do not have to take anyone's word for it. You check the certificate.
Strip away the diplomacy and the scheme is a chain of physical and documentary controls. Rough diamonds destined for export are presented to the government authority. They are sorted, weighed in carats and valued. They are then sealed into a tamper-resistant container. A certificate is issued against that specific sealed parcel — uniquely numbered, forgery-resistant, recording the country of origin, the carat weight, the value, and the parties. The parcel and its certificate travel together, and the parcel is not to be opened again in transit. On arrival, the importing participant country confirms receipt back to the exporter.
Each link in that chain is there to defeat a specific trick. The sealed container stops stones being swapped after valuation. The unique number stops a certificate being reused. The participant-only trade rule stops conflict stones being "washed" through a non-member country. The confirmation of receipt closes the loop so a shipment cannot simply vanish from the record. It is deliberately boring, and the boredom is the feature.
In Sierra Leone the engine room of the scheme is the Government Gold and Diamond Office (GGDO). This is the state body that receives rough presented for export, values it, and sits at the heart of the certification. The valuation the GGDO assigns is not a side-formality — it becomes the value written on the Kimberley Process certificate, and it is the base on which the 3% diamond export duty and the 0.3% advance income tax are charged. Valuation, taxation and certification are therefore bound together in a single supervised act.
For a buyer, the GGDO is the name to anchor on. A legitimate rough-diamond transaction out of Sierra Leone will have a GGDO valuation behind it and a KPCS certificate in front of it. The two match. If a seller can produce neither — if the stones have simply "come from the fields" with no office, no valuation and no number — then whatever they are offering has not been through the channel that makes a Sierra Leonean diamond verifiably conflict-free.
Sources: Kimberley Process official scheme documents; National Minerals Agency, Sierra Leone; Government Gold and Diamond Office; Mines and Minerals Development Act 2022.A certificate is only useful if you can read it, and reading it is not hard once you know the fields. Every KPCS certificate carries a unique serial number — the first thing to record and to verify with the issuing authority. It states the country of origin, which for your purposes should be Sierra Leone, not a transit country. It records the carat weight and the value, which should reconcile with the GGDO valuation and with the sealed parcel's contents. It names the exporter and the importer. And it is a forgery-resistant document — printed on controlled stock, not a photocopy or a PDF someone emailed you in isolation.
Three checks turn those fields into assurance. First, confirm the serial number and the issuing authority directly — a number that the authority cannot confirm is worthless no matter how official the paper looks. Second, confirm the parcel seal is intact and matches the certificate; a certificate attached to an already-opened or re-sealed parcel has lost its chain. Third, reconcile the weight and value against the GGDO valuation. When all three line up, you are holding the thing the scheme was built to give you: a verifiable, conflict-free provenance.
If you remember one thing: the certificate's unique serial number must be verifiable with the issuing authority, and the sealed parcel must match it. A certificate you cannot verify, or a seal that has been broken, breaks the guarantee — however convincing the document appears.
Honesty about the scheme's limits is part of using it well. The Kimberley Process governs rough diamonds crossing borders. The moment a diamond is cut and polished, it falls outside the scheme's scope — a KPCS certificate is not issued for polished stones. The industry fills that gap with the System of Warranties: a written assurance passed from seller to buyer at each stage of the polished supply chain, declaring the diamonds were sourced from KPCS-compliant rough. So for rough you rely on the certificate; for polished you rely on warranty statements plus reputable grading.
The scheme also addresses conflict financing specifically — stones used to fund rebel movements against legitimate governments. It is not, in itself, a full environmental or labour-standards audit of a mine. Those are real and worthwhile concerns, but they are addressed by other instruments and by a dealer's own due diligence, not by the KPCS certificate. Knowing precisely what the certificate does and does not promise keeps you from either dismissing it or over-reading it.
Putting it together, buying conflict-free rough from Sierra Leone follows a clear path. Deal only with a licensed dealer and exporter — the same licensing regime that governs gold under the Mines and Minerals Development Act 2022 governs diamonds. Require that the rough be valued by the GGDO, and treat that valuation as both your tax base and your provenance anchor. Require a Kimberley Process certificate against a sealed, tamper-resistant parcel, and verify its serial number with the issuing authority. Reconcile the certificate's weight and value against the GGDO figure and the parcel. Only then does money move.
None of these steps is exotic, and a legitimate exporter will expect every one of them. The sign of a sound counterparty is not that they are offended by your checks — it is that they have the documents ready before you ask. If you would like the certified, GGDO-valued channel walked through on a real parcel, that is exactly what our desk is for.
See also our guide on how to buy diamonds in Sierra Leone for the full transaction procedure, and export duty & taxes for how the 3% diamond duty and 0.3% advance tax are calculated on the GGDO value.
Buying bullion, sourcing rough, or arranging lawful export — our desk in Bo answers every serious enquiry within one business day.