Characteristics of Clastic Sediment(1) Clastic sediment is divided into four main size classes. a Gravel >2mm Sand 0.0625to2mm Silt 0.0625t00.0039mm Clay <0.0039mmCharacteristics of Clastic Sediment (1) ◼ Clastic sediment is divided into four main size classes: ◼ Gravel >2mm ◼ Sand 0.0625 to 2mm ◼ Silt 0.0625 to 0.0039mm ◼ Clay <0.0039mm