Pebble Stone is a class of rock with a particle size of 464 mm (0.162.52 in) based on the Udden-Wentworth scale of sedimentology. Pebbles are generally considered larger than granules (24 mm (0.0790.157 in) in diameter) and smaller than cobbles (64256 mm (2.510.1 in) in diameter). It has been broken down from larger pieces. They are a growing medium that is most often used in hydroponic gardening. The Pebble is made available by us for commercial uses.