Lava Rock
Also known as: volcanic rock, scoria
Lava rock is a lightweight, porous volcanic stone available in red, black and brown tones. Because it is non-combustible and insulating, it is popular for fire features, drainage and decorative ground cover.
In simple terms
Lava rock is the airy, bubbly red or black stone formed from cooled lava. It weighs far less than regular rock, so it is easy to spread, and its porous surface holds moisture and resists fading.
In depth
Its cellular, vesicular structure makes lava rock roughly half the weight of comparable rock by volume, so a cubic yard covers more area and is lighter to haul. The pores hold water and slowly release it, moderating soil temperature and moisture. Lava rock is non-combustible and heat-stable, which is why it is used in gas fire pits and around fire features. The trade-off: its rough surface can be uncomfortable to walk on barefoot and can trap fine debris.
Why it matters
Lava rock combines fire safety, water-wise moisture retention and a bold color that does not fade — a long-lasting, low-maintenance choice for accent beds and fire features.
Common mistakes
- Using lava rock as a primary walking surface — its sharp, porous texture is hard on bare feet.
- Assuming all lava rock is fire-pit safe; only use rock rated for fire features in a gas fire pit and never trap moisture that can cause popping.
Examples & uses
- Fill and accent stone around gas fire pits and fire features.
- Bold-colored ground cover in decorative beds.
- Lightweight mulch alternative that will not decompose.