Grain rounding

Grain rounding is part of the granulometry and describes one of three properties of the grain shape:

• Grain shape
• Grain surface
• Grain rounding

Grain rounding deals with particles that play an important role in many technical and scientific areas. Examples are building materials such as sand, cement, concrete and gravel, production processes with powdery materials such as flour, plastic granulate, pigments and ceramics, and various geoscientific disciplines, in particular sedimentology and soil science .

The grain rounding is influenced by various factors: On the one hand by the hardness of the grain, which can be machined well (soft) or poorly (hard) depending on the degree of hardness. The cleavage of the mineral in question also plays a role. If the grain has very good or even complete cleavage properties, it is preferably split into smaller grains with the same habit during longer transport and high mechanical stress . The rounding plays a subordinate role here. If, on the other hand, the mineral is indistinct or poorly cleavable, the rounding becomes increasingly clear.

The duration and type of transport also play a major role. When transported over long distances and / or for a longer period of time with high mechanical stress due to abrasion , collisions and weathering , the grain is well rounded; if handled the opposite way, it remains angular, angular and misshapen. However, it has to be said that these factors play a role to varying degrees depending on the hardness of the mineral in order to achieve the same results.

A distinction is made between the different grain shape stages:

• very angular
• angular
• rounded
• round