The application of high-pressure abrasive water jets (AWJ) has evolved quickly in some fields of engineering. At Polytechnic School, University of Sao Paulo, one application has particular interest that is the cutting of friable materials, as rock and ceramics. The main aspect in this field is the cut at the beneficiation process of end product in dimension stone plates. How much the cut of plates, by different kind of AWJ methods, was the research of a PhD Work of one of the authors. The abrasive water jet equipment, installed in the Laboratory of Rock Mechanics of the Mining and Petroleum Engineering Department, was used. Some fundamentals considerations regarding, the employed single and multiple passes methods of AWJ to cut rocks, are discussed.