What is the maximum and minimum size range for pebble, sand, and clay?

Based on the Wentworth scale the Maximum size for a pebble is 64 Millimeters and the minimum size for a pebble is 5 Millimeters. There are a variety of clifications of sand the Maximum size of all of the sand clifications is less than 1 Millimeter to a minimum of larger than 1/16th of a Millimeter and Clay would be less than 1/256th of a Millimeter.