This quartz sand comes from a small extraction and processing company based in northern Bavaria.
It is advantageous to fill the bottom of an incense burner with sand in order to contain the heat and protect the surface underneath. In charcoal incense burners, lines are drawn in the sand on which the charcoal is placed in order to achieve under-ventilation and thus a better glow. In incense burners, sand is useful when wax spills out of the tealight holder, making it easier to remove later. Also, heat intensity can be adjusted by adding or taking away sand to raise or lower the tealight.