Very few grills use actual lava rocks anymore, because BBQers (yes, they're different from grillers, look it up) would use them until the porous lava rocks became completely saturated with sauce and fat, thus setting up for a conflagration that would melt the siding off your trailer. read more
GrillPro, one of the Onward Manufacturing Companies, makes a universal fit rock grate that fits most sizes of gas grills. Alternative to Lava Rocks Of course, you don't have to use lava rocks. read more
Lava rocks are not required for use on a gas barbecue. Lava rocks are used to help create the traditional smoky barbecue flavor from the fats that drip onto them and then evaporate. Common grills today use vaporizer bars that are placed above the flames instead of lava rocks. read more