American Fireglass LAVA-S-10 American Fire Glass Small Sized Black Lava Rock &ndash; Porous, All-Natural, 1/4 Inch to 1/2 Inch Thick x 10 Pounds All-natural lava rocks: formed as volcanic magma rises to the surface then cools and releases gases, these small fire rocks can withstand the most extreme temperatures without damage or crumbling, making them a beautiful addition to your fire feature! Sourced in the USA. Indoor or outdoor use: lava rocks are the perfect choice for fire bowls, fire pits, and indoor or outdoor fireplaces (liquid propane or natural gas). use these fire pit rocks on their own or as a base or filler for other ornaments. High quality, low maintenance: durable, long-lasting and cost effective, American fire glass Black lava fireplace rocks come in a variety of Sizes, have a porous surface and require very little maintenance. Enhance your home oasis: Black lava rocks are a low-cost way to give your fire feature an exotic, tropical and classy look. Naturally occurring fire pit rocks look great and have a fascinating burning effect. Versatile: American fire glass lava rocks go beyond fire features. The all-natural rocks are great in soil to retain moisture for plants and also work well as an addition to aquariums and ponds.