American Fireglass is tempered glass specially made for use in fireplaces and firepits, and burns cleaner and more efficiently than conventional gas logs. It will not melt, degrade or emit toxic fumes. Looks great in both indoor & outdoor fireplaces, as well as firepits, vases or as a decorative feature in your patio landscape. An average fireplace takes between 50 and 80 pounds of fireglass. You can create your own color combinations by mixing your favorite colors together. Using 1/4" Clear Fireglass as a "filler" can cut down on your overall costs. A 2-3" thick layer of fireglass is recommended for a beautiful look and feel.