I am looking for rock that have the smallest nano sized pores.
I am looking for Rocks and sub straights that allow air and water to pass through but not allowing other materials to pass through.
I will need a list of the best 20 rocks that are common and not expensive.
I will need you to provide the sources and links to your sources for me to read and verify in English.
I am experienced in writing geology tasks. I have a bachelor's degree in geology and j have vast knowledge in the field whereby I will use my knowledge to deliver quality work. I am preferable to doing this task.