* Different rock types: Different rocks have different hardness, mineral composition, and fracture patterns. This leads to variations in how they break down when weathered.

* Weathering processes: There are several types of weathering, including:

* Physical weathering: This involves the breakdown of rocks by mechanical forces like freezing/thawing, abrasion, or pressure release. The size of the fragments depends on the force applied.

* Chemical weathering: This involves the chemical breakdown of rocks by processes like oxidation, hydrolysis, or dissolution. Chemical weathering can produce fragments of varying sizes depending on the chemical reaction.

* Time: The amount of time a rock has been exposed to weathering influences its breakdown. Longer exposure results in smaller and more fragmented pieces.

* Environment: The environment where weathering occurs plays a role. For example, rocks in a desert will weather differently than rocks in a humid climate.

In short, the size of weathered rock fragments depends on a combination of factors, making them highly variable.