Here's why:

* Angular: This refers to their shape, which is irregular and sharp-edged.

* Volcanic fragments: They are pieces of erupted material.

* Bombs: This term specifically denotes fragments that are large enough (typically larger than 64 mm or 2.5 inches) to solidify in flight before landing.

Volcanic bombs can have a wide range of sizes and shapes, depending on the eruption dynamics. They can be quite dangerous, as they can travel considerable distances and cause significant damage.