Granite is a type of igneous rock known for its durability and resistance to weathering. However, like all rocks, granite does have weaknesses and can break along specific planes called cleavage.

However, granite doesn't actually have a true cleavage in the same way that some minerals do. Minerals with cleavage break along specific planes of weakness in their crystal structure. Granite, on the other hand, is a composite rock composed of multiple minerals, and its structure is not as uniform.

Instead of cleavage, granite exhibits "joint systems". These are fractures or planes of weakness that form in the rock during its formation or after due to stresses from tectonic movements or cooling.

Here's what's important about joint systems in granite:

* They are not as predictable as cleavage in minerals. Joint systems can be irregularly spaced and oriented.

* They influence how granite breaks. When subjected to stress, granite tends to break along existing joint planes. This can create large blocks of granite, which can be seen in quarries or in natural rock formations.

* They can be exploited for quarrying. Quarry operators will look for well-developed joint systems to extract blocks of granite.

In summary, while granite doesn't have true cleavage, it does have "joint systems" that act as planes of weakness influencing how it breaks. This understanding is important for both geological and practical reasons.