Onlyfire Fire Pit Fireplace Lava Rock Transform any dull fire pit to a warm and exotic flair Natural lava rocks are excellent base layers and cost-effective fillers for gas fire pits and fireplaces. These black or red fire glass have a naturally porous surface, which determines their superior gas fluidity. They can withstand extremely high temperatures without damage, degrade or crumbling. Both visually and ambitiously, the volcanic rock is a low-cost way to bring exotic fire features to you. Lava rocks work great as a firebase underneath fire glass for a fire pit or fireplace. Complements many landscapes by adding texture, color, and depth. Great for indoor and outdoor use around your home or business. Mr. Fireglass offers two colors and different sizes of lava rocks for you to choose Reasons to Choose Our Natural Lava Rocks Clean-burning Fire Flame Improve Flame Performance Withstand High Temperature Low Maintenance Adds Brilliant Color to the Light of the Fire Safe to Use Gas Compatible Decoration for Fire Pit & Fire table These lava rocks have natural a porous surface, which can help spread the gas dispersion in all directions to improve the flame performance. It works great as a firebase underneath fire glass for fire pit or fireplace. Activate Oxygen Ions in Water and Optimize Water Feature Volcanic rocks can activate the oxygen ions in the water and promote the metabolism of plants and animals. The porous structure can absorb harmful bacteria, residues and harmful heavy metal ions to keep the water in the tank clean. Widely Used in Homes and Other Places Natural lava rocks with an earthy, natural look, It works well as a transitional rock between the flame and fireplace. Both visually and ambitiously, the glass rock is a low-cost way to bring exotic fire features to you. HOW MUCH YOU NEED? Round Fire Pit Diameter (A) x Diameter(A) x Glass Depth (B) / 24 = Glass (lbs.) We recommend a minimum 2” of fire glass depth for most installations. For example, a 24" diameter fire pit at the recommended 2” of fire glass depth: 24 X 24 X 2 / 24 = 48 lbs. Rectangular Fire Pit Width (A) x Fireplace Depth (B) x Glass Depth (C) / 19 = Glass (lbs.) We recommend a minimum 2” of fire glass depth for most installations. For example, a 30" X 10" fire pit at the recommended 2” of fire glass depth: 30 X 10 X 2 / 19 = 31 lbs. Square Fire Pit Width (A) x Width (A) x Glass Depth (B) / 19 = Glass (lbs.) We recommend a minimum 2” of fire glass depth for most installations. For example, a 20" fire pit at the recommended 2” of fire glass depth: 20 X 20 X 2 / 19 = 42 lbs. Indoor Fireplace (Front Width (A) + Back Width (B) )/2 x Fireplace Depth (C) x Glass Depth (D)/19 = Glass (lbs.) We recommend 2" - 4" of glass depth for most fireplaces. For rectangular and square fireplaces, use the same front width as back width.