The potential of abrasive waterjet technology was investigated as a method to polish Z-blocks of synthetic quartz crystals. The polished surfaces were characterized by surface roughometer and scanning electron microscopy. The main factors affecting the surface roughness and the erosion mechanisms related to material removal were analysed. It is found that abrasive mesh, water pressure and jet incidence angle are the main factors affecting the surface roughness. By contrast, the influence of traverse speed on the surface roughness is small. Under certain controlled conditions, the erosion mechanisms of synthetic quartz crystals are plastic flow, leaving a crack-free surface by low-middle pressure micro abrasive waterjet.