Brown Lava Rocks create a unique effect and a great conversation piece! Rocks sizes range from .5" to 1.25" in diameter and are mostly brown with hints of gray and red. All fire rocks feature a rough volcanic surface. Rocks are all natural and durable, withstanding temperatures up to 1472° F / 8 ° C and natural weathering and will not melt, break or emit smoke when burned at high temperatures. Replace ceramic logs with lava rocks for a distinctive look for your fireplace or fire pit. In addition to being used in a fire pit or fireplace, lava rocks can be used in landscaping and gardens.