Vermiculite granules are the great finishing touch to the realism of a great gas log fire. The granules are clean and add to beauty of the fire. They give a bed for the glowing ember and provide shelter for the burner. The vermiculite granules will fill in any blank space. These gas log vermiculite granules are manufactured by Real Fyre and are meant to be used only with vented Peterson Flame Pan and Glowing Ember gas burners.