After shave alum stone.
The alum or potassium alum is a mixture of aluminum and potassium salt of sulfuric acid which at room temperature is presented as a colorless, solid, odorless and totally natural product. It is a perfect ally for after shaving thanks to the astringent and hemostatic capabilities. This natural mineral is also used as a natural hypoallergenic.
Potassium alum, mineral present in nature with an astringent action