Vesicular and Pyroclastic Igneous Rocks

Scoria Pyroclastic volcanic rock made of fragmental pieces of rock and ash cemented together by 

Pumice Pumice is sponge-like pyroclastic volcanic rock, with a very low density (i.e., below that of water), and light in color (i.e., white to gray), it may be glassy or dull, and fully riddled with holes. It is used as an abrasive (e.g., pumice stone, lava soap). 

Tuff Tuff is a pyroclastic igneous rock with a fragmental texture and is often friable (loosely held 

Obsidian Dark amorphous igneous rocks with a rhyolitic chemical composition, conchoidal fracture and brittle, sometimes devitrification figures. 

Fragment or clast size Pyroclast or fragment type Consolidated rock name 

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