Trap rock, Basalt, Gneiss - Abrasion index above 0.10 6. Typical non-abrasive rock is clean Limestone (Marble) - Abrasion Index below 0.10 7. fines or ”0-X mm” material is normally below 2 mm. -0.075 mm is called filler Recommendations: Best (B), Good (G), Possible (P)
