Which rock type is described as often highly fractured and can contain pumice fragments?

The rock type often described as highly fractured and capable of containing pumice fragments is rhyolite. Rhyolite is an igneous rock that is the extrusive equivalent of granite, characterized by its fine-grained texture. It typically forms from the rapid cooling of lava at Earth's surface and can exhibit various textures, including the presence of phenocrysts and vesicles. The fractures in rhyolite can result from the cooling process and subsequent tectonic activity, allowing for the incorporation of pumice, which is a volcanic rock that forms when lava cools quickly and traps gas bubbles, resulting in a lightweight, porous material.

Understanding rhyolite's composition and formation helps to clarify its distinctive features, like the presence of pumice fragments, which aligns with the description provided in the question. Other rock types in the options do not typically match the characteristics associated with rhyolite in terms of fracture patterns or the ability to contain pumice.