The "grain property" of rock fragments refers to the texture of the rock, specifically focusing on the size, shape, and arrangement of the individual mineral grains or fragments that make up the rock.

Here's a breakdown of the different aspects:

* Size: This refers to the diameter of the individual grains. Rocks can be classified based on grain size, ranging from very fine (clay) to very coarse (boulders).

* Shape: The shape of the grains can be rounded, angular, or irregular.

* Arrangement: This refers to how the grains are packed together. They can be well-sorted (all grains are similar in size) or poorly sorted (a mix of grain sizes). They can also be randomly arranged or show a preferred orientation.

Here are some examples of grain properties and what they tell us about the rock:

* Well-sorted, rounded grains: Suggests the rock has been transported a long distance and subjected to significant weathering and erosion.

* Poorly sorted, angular grains: Suggests the rock was formed close to its source and has not been transported far.

* Oriented grains: Indicates the rock was formed under pressure, possibly during deformation or metamorphism.

The grain property of rock fragments is an important aspect of rock identification and can provide clues about the rock's origin, history, and formation conditions.