Midwest Hearth Rock Wool for Gas Log - 6 oz. Bag ENHANCE YOUR FIREPLACE - Creates a realistic glowing ember effect in your gas fireplace or gas log set! ADDS REALISM - Glows like real coals where the flame touches the embers. NATURAL GAS & PROPANE - Compatible with NG and LP gas appliances. GENEROUS SIZE - 9" x 12" bag (6oz) is suitable for most fireplaces. LASTS FOR YEARS - Mineral composition resists extreme temperatures.