Pumice stones are excellent soil conditioners. Their unique structure enhance the air porosity in soil allowing roots to breath healthy.
Pumice stones are kind of volcanic rock which is very light in weight as well as porous. Using them in soil mix increase the over all porosity of the soil. It also helps to hold good amount of moisture without letting soil soggy.
Pumice stones are also used for mulching purpose as well as to grow bonsai plants exclusively. It proves to be very effective component of Soil mix for cactus and succulent plants.