... pebbles, Silica grinding ballsProperty: Round grayish silica stoneSize: 2-4cm, 4-6cm, 6-8cm, 8-10cm, 10-12cm, 12 ... . The mining limitation period is over 30 years.2. Quality guarantee--our silica pebble has high content ... welcome any interested customer come to visit us.4. Our own logistics company will provide you a ... grinding silica man-made pebbles (round,1-2cm,2-4cm,4-6cm,6-8cm,8-10cm,10-12cm,12-15cm ...