A PCD polishing tool is a machining/polishing instrument whose active surface is made of or tipped with PCD (polycrystalline diamond) material, designed to deliver very high-quality surface finishes (including mirror or near-mirror finishes) on workpieces. For example, one supplier describes a PCD polishing tool “dedicated to mirror polishing, and roughness is below Ra 0.03.” These tools are used in ultra-precision finishing operations, often on non-ferrous metals, composites, plastics, optical surfaces, moulds, etc. Because PCD is extremely hard, wear-resistant and can maintain geometry, these polishing tools can reduce manual labor, improve consistency, and extend service life compared to conventional polishing/finishing tools.