Here's why:

* Angular fragments: Breccia is characterized by its angular rock fragments, unlike a conglomerate which has rounded fragments.

* Finer matrix: The angular fragments are embedded in a finer-grained matrix, which can be composed of volcanic ash, dust, or other smaller fragments.

* Volcanic activity: Breccia can be formed by various processes, but the specific type you're referring to is likely a volcanic breccia. This type forms during volcanic eruptions due to the explosive fragmentation of lava and surrounding rock.

Other types of breccia:

* Tectonic breccia: Formed by faulting and fracturing of rocks.

* Impact breccia: Formed by the impact of meteorites or asteroids.

* Sedimentary breccia: Formed by the accumulation and cementation of angular rock fragments in a sedimentary basin.

Let me know if you have any other questions about rocks!