American Fireglass ZIR-PWDBLLST-10 Powder Blue Luster Zircon Fire Glass, 10 lb Color-infused, high quality molded glass, silica infused, sifted, polished, packaged and quality controlled to perfection. 1" thick, chunkier in size, Smooth diamond-like shaped pieces with flattened bottoms, available with or without a luster semi-reflective coating. For use with fire bowls, fire pits and fireplaces, indoors or outdoors (liquid propane or natural gas), or as a decorative landscape. This glass can withstand higher temperatures compared to logs, lava rocks, stones, etc. Does not emit any toxic fumes, smoke, ash, or soot. Requires very little maintenance.