Not every diamond is destined for jewelry. In fact, about are unsuitable for adornment due to heavy inclusions or poor color. These "boart" or industrial-grade stones are purchased by companies in the tooling, drilling, and tech sectors. Because diamonds are the hardest known natural material, they are essential for industrial cutting, grinding, and polishing tools. 5. High-End Jewelry Maisons
The most prominent buyers are "Sightholders." These are elite diamond manufacturing and trading companies authorized to buy directly from major mining giants like De Beers or ALROSA. These sales happen at "sights"—exclusive events held several times a year. Sightholders must meet strict financial and ethical standards to maintain their status, often buying hundreds of millions of dollars in rough stones annually. 2. Diamond Manufacturers (The Cutters) who buys rough diamonds
While some Sightholders cut their own stones, many other rough diamonds are sold to independent manufacturing firms, primarily located in global hubs like (where roughly 90% of the world's diamonds are cut) and Antwerp, Belgium . These buyers are experts in "planning" a stone—using 3D scanning technology to decide how to cut a rough crystal to maximize its weight and clarity. 3. Professional Traders and Wholesalers Not every diamond is destined for jewelry
Middlemen play a vital role in the "secondary market." These traders buy rough parcels from smaller mines or at auctions and break them down into smaller, more specific lots. They then sell these tailored packages to smaller manufacturers who may only need specific sizes or qualities of stones. 4. Industrial Buyers Because diamonds are the hardest known natural material,
In summary, the rough diamond market is a closed loop of experts. From the industrial giants who need grit for drill bits to the master cutters in India, these buyers turn opaque, pebble-like crystals into the calibrated gems and tools the world relies on.