The abrasive used in ultra high-pressure water jet cutting systems is one of the important elements in the kerfs opening. To cut rocks, metals; ceramic, and other hard materials, the abrasive more used is the garnet mineral. Their technological characteristics are important for this cutting technology and can influence in the definition of a powdered material as an abrasive; mainly they are size, hardness, and the geometric form of the grain. The treatment tailings of the monazite's sand ore of Espirito Santo State, processed at the plant in Buena are constituted mainly of ilmenit and garnet. Preliminary rehearsals accomplished on sample revealed that the tenor in garnet is superior to 20% in weight. A concentrate, prepared in laboratory was rehearsed for determination of their main technological characteristics. The mineralogical constitution reveals almandine/almandite existence, and some grossular. The size rehearsals accomplished in laser diffracting beams (Malvern) show that the same has appropriate diameter grains to be used as powdered abrasive. His form revealed by pictures in binocular magnifying glass shows that the same is adapted for job as powdered abrasive, so much for sandpaper, or abrasives bricks as well as for use in advanced water jet cutting systems.