浑圆度受下列因素的控制,这些因素是搬运物质的粘度、搬运的速度与距离、河床底部的结构(是砾石的,还是砂质的),此外还应加上随颗粒一同输送的物质的结构以及颗粒的重量、硬度、形状和可劈性。由于这些因素的复杂性,一个颗粒的滚磨历程只能大致从它的浑圆度来决定。也许下述观察对读者是有帮助的。燧石的抗磨力很高,石英岩与石英斑 Roughness is governed by factors such as the viscosity of the material being handled, the speed and distance of handling, the structure at the bottom of the river bed (whether gravel or sandy), and the structure of the material being transported with the particles As well as the weight, hardness, shape and cleavability of the particles. Due to the complexity of these factors, the rolling history of a particle can only be roughly determined by its roundness. Perhaps the following observations are helpful to the reader. High chert abrasion resistance, quartzite and quartz spots