Provenance ledger for 480,000 certified diamonds
A consortium of mines, cutters, graders, and retailers wanted a single source of truth for diamond provenance — from mine to retail, with consumer-facing QR verification. We architected and deployed a permissioned Hyperledger Fabric network spanning 8 mines, 22 cutting houses, 6 grading labs, and 90 retailers across 4 continents.
The problem
Synthetic and conflict diamonds had eroded consumer trust. Each step of the supply chain — mining, sorting, cutting, polishing, grading, distribution, retail — used incompatible certification systems, often paper-based. Disputes took weeks to resolve and provenance claims could not be independently verified by the consumer.
The solution
A permissioned Hyperledger Fabric network where each consortium member runs their own peer node. Every state change — extraction, custody transfer, cutting event, grading result, retail listing — is signed by its originator and immutably written. Consumers scan a QR on the certificate to see the full chain on a public-readable web view.
What we built
Permissioned Hyperledger Fabric
126 nodes across 4 continents, 8 organisations, 3 channels. Sub-second commit on the hot path. PBFT consensus inside each consortium tier.
Cryptographic identity at every step
Each mine, cutter, grader, and retailer signs every transaction with a hardware-secured key. No anonymous writes possible.
IoT scale + camera at every handoff
Custody transfers logged with weight, photo, GPS, and timestamp from a tamper-resistant terminal. Field-rugged Android with a TPM module.
Consumer QR verification
Every retail certificate has a unique QR. Scan it and see the full chain: country of origin, cutting house, grading lab, retailer — without revealing internal pricing.
Native iOS & Android operator apps
Mine, cutter, grader, and retailer operators each have a tailored app — they only see and write the data they are authorised for.
Consortium analytics dashboard
Aggregate flow analysis, dispute heatmaps, throughput per cutter, certification accuracy. Used by the consortium board for monthly reviews.
How it’s built
The numbers
“Before this, proving a stone’s journey took weeks of paper chasing. Now a customer in Dubai scans a QR and sees the chain back to the Botswana mine in two seconds.”
— Group COO, Diamond Consortium
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