Why do sandstone rocks sometimes have holes in them?

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. The holes that are left are great places for storing water or oil. Some sandstones have more holes than other depending on the amount of calcite or quartz that fills in between the sand grains. Find out more about rocks and minerals at www.MiniMeGeology.com!