Pumice stones | geology behind floating stone like in ramayan

It is mentioned in the epic Ramayana that Ram Setu was built by the son of Lord Vishwakarma when Lord Rama needed to cross the sea to reach Lanka. The epic mentions that whenever the name of Lord Rama was written over any stone, it started to float in the sea water.
As we are human and some questions occures in our mind for checking that presence of that thing in actual world.

YES IT IS TRUE, PUMICE STONE FLOATES OVER THE WATER. IT IS GEOLOGY DUDE....:-)
Any object floats in any liquid when the weight of the liquid, displaced by the fraction of the object immersed in the liquid, is equal to the entire weight of the object itself. Pumice called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals. It is typically light colored. Pumice is created when super-heated, highly pressurized rock is violently ejected from a volcano . The unusual foamy configuration of pumice happens because of simultaneous rapid cooling and rapid depressurization. The depressurization creates bubbles by lowering the solubility of gases (including water and CO2 ) that are dissolved in the lava, causing the gases to rapidly exsolve (like the bubbles of CO2 that appear when a carbonated drink is opened). The simultaneous cooling and depressurization freezes the bubbles in the matrix.
Pumice has an average porosity of 90%, and initially floats on water. Pumice is widely used to make lightweight concrete or insulative low-density cinder blocks. When used as an additive for cement , a fine- grained version of pumice called pozzolan is mixed with lime to form a light-weight, smooth, plaster-like concrete.