Heated crystal rock generates negative ions in the air. These negative ions kill bacteria and other harmful organisms while purifying the air, and increase overall air quality. You can scent them with fragrance oil, essential oils, or use them unscented. Heat them in a tart warmer, potpourri pot or use a candle warmer with the rock in tempered glass. You can also use the rock unheated. It comes in a 16 ounce jar with 2 ounces of fragrance, so shake up the jar and open the lid. Will fragrance a bathroom very nicely. Replace the lid and shake up every 5 days or so. Will last up to 1 year.