What is the role of color and size sorting machines in rough screening?

• A. They engrave the stones with marks
• B. They physically polish the stones during sorting
• C. They automatically sort rough stones by estimated color and size to guide yield potential
• D. They determine final price for sale

Answer: (C)

Automated color and size sorting is about pre-sorting rough diamonds by estimated color potential and size to guide which stones to prioritize for cutting and overall yield. In rough processing, color and size are major drivers of value and profitability. These machines quickly assess a stone’s apparent color and approximate carat range as it moves through the line, directing stones into different processing streams based on those estimates. That early separation helps maximize what comes out of the process, by focusing on stones with higher potential and routing smaller or lower-potential pieces to other paths.

They do not engrave or polish stones, and they do not determine final sale prices. Final pricing comes later, after actual cutting, polishing, and market assessments.