Why Does Scoria Have Holes?

Scoria is a highly vesicular, dark-colored volcanic rock that may or may not contain crystals (phenocrysts). ... The holes or vesicles form when gases that were dissolved in the magma come out of solution as it erupts, creating bubbles in the molten rock, some of which are frozen in place as the rock cools and solidifies.

What are the holes in scoria called?

Pumice and scoria are extrusive rocks and form outside of the volcano usually on top of lava flows. The top of these lava flows become very frothy and when they cool the gasses in the lava expand and escape forming air hole or vesicles in rock.

What does it mean if a rock has holes in it?

Posted by Tracy Diane Jones. Sandstone rocks with holes are known as porous sandstones. The porosity is formed when spaces are left during the cementation process. The cementation process is when a liquid form of a mineral such as calcite or quartz “glues” the sand grains together.