... and making jewelry, jade, agate. ♦ Grinding of gray cast iron, white cast iron, bronze, brass, ore, bone, glass, leather, rubber ... , plastic and the thermal sensitive material.3. Partical size,Black silicon carbide F12-320# F320-2000# JIS240 ... 100#-180# 220# -240# w63 - w20# w14 - w598.5 98.0 97.0 96.0 93.00.20 0 ... 0.20 0.30 0.30 2.5 0.60 0.80 1.20 1-3 3-5 5-8 Silicon Carbide grit