- Desiccant is a drying agent. It induces or sustains a state of dryness (desiccation) in its vicinity. It absorbs and holds humidity to itself. - Silica gel is a a pure, vitreous, porous form of silicon dioxide made from sodium silicate. It is purified and processed into either granular or beaded form. Its high absorption capacity is attributed to its millions of tiny pores. The mechanism of absorption is purely physical, with no change in size or shape of the particles even as they become saturated. Even when fully saturated, the material still looks and feels dry.