POROUS QUARTZ is made by a monolithic silica with the hierarchical porous structure by the sol-gel technology. Large amount of oil can be loaded due to the high porosity greater than 80% showing the long-time lasting. It has high affinity for all fragrance oils, which are absorbed spontaneously by the capillary phenomenon. You can also use it repeatedly. Just to add oils when the fragrance is vanished. The appearance of Porous Quartz® will be turn to transparent when oils are included.