Surface polishing evaluation for faceted diamond

Surface imperfections on diamonds significantly affect their appearance and market value. To improve grading consistency and reduce evaluation time, we developed two automated imaging systems that capture surface features across all facets of a diamond using specular reflection. The first system targets the diamond’s table, automatically aligning it perpendicular to the camera for high-quality surface evaluation. The second system uses a wireframe model to guide precise alignment and sequentially image all remaining facets. For the girdle, images are captured from 16 orientations under dark-field illumination with variable exposure settings to enhance dynamic range and prevent saturation. Both systems resolve features as small as 3 μm and are optimized for round brilliant cut diamonds up to 1 carat. These systems enhance grading accuracy, increase consistency, and provide objective, reproducible results to support traditional gemological methods.