The smoothness of a cut on gemstones depends on three main factors: blade quality, grit size, and kerf thickness. For the cleanest and smoothest cuts, a thin kerf diamond blade is typically the best choice — it minimizes heat, material loss, and edge chipping. High-precision blades, like those offered by UKAM Industrial Superhard Tools, are specifically engineered for gemstone cutting and can deliver excellent results with consistent smoothness.