Sodium metasilicate is Na₂SiO₃, a form of waterglass. The molecules of this chemical are of the normal angstrom or nanometer scale. Also known in the dissolved form as waterglass — it is a reactive chemical used for sealing pores and causing colloidal particles to sediment out of solution. The most common use in oilfield chemistry is in drilling fluids as a borehole stabilizer — where the pore sealing properties are useful. When exposed to variable pH, dissolved alkali earth metals (like calcium or dissolved salts of calcium) or dissolved organic materials, Na₂SiO₃ is prone to polymerization. This is the main reason it is used as a borehole stabilizer and even as a zone sealant/water shutoff agent.