
Sandstone
When exposed to the heat from a fire pit, sandstone rocks can easily trap moisture, causing them to crack or explode. Accumulated pressure makes the stones unsafe and could lead to debris being thrown.
Sandstone cannot withstand rain and other weather that leads to temperature changes. It can hold water well on the inside, but being near the heat of the fire causes it to explode. You can generally see sandstone discolor or crack, letting you know the durability isn’t good.
To minimize the risk of explosions, go with lava rocks or fire bricks instead. Both options are designed to handle intense heat and high temperatures.
Shale
Even when placed on dry surfaces, shale can absorb water from the environment. This water absorption will explode inside a fire pit, making shale a safety hazard. The water absorbed and trapped inside shale will turn to steam quickly, fracturing or exploding the rock.
A good alternative would be fire glass, which provides an appealing flame pattern within a safe structure. You can also consider using lava rocks to withstand the heat and reduce the risk of cracking or exploding.
Limestone
Many homeowners believe limestone’s durability and strength make it an excellent choice for fire pits. The assumption is that these stones are fire-resistant and can absorb heat moderately. Limestone readily absorbs moisture, but this makes it rapidly expand when exposed to heat. As a result, the stone will crack or even explode because of the trapped steam.
Whether it’s from rain or dew, the moisture absorption is extremely dangerous when exposed to heat, making it best to keep limestone away from fire pits. The trapped water could explode quickly and cause the stones to shatter violently.
River Rocks
The trapped moisture inside these stones can explode when placed near a fire pit’s high heat. Remember that some open spaces allow decorative rocks to trap and hold liquid readily, but some cannot, increasing the odds of explosions. When this happens, the exploding river rocks, such as polished black river rock, could injure you or others nearby.
To learn more about alternative rocks that can be placed in a fire pit, speak with a trusted decorative rock, stone, and beach pebble supplier. These professionals can help with your landscaping projects and give you usage ideas for river rocks. The aim is to select good insulators, which river rocks are not.
For advice on how to properly use decorative rocks in your landscape, reach out to the experts at RS&P Rocks Stones & Pebbles, a premier landscape rock and supply superstore. We specialize in drought-tolerant landscaping materials, including a variety of colored river rock and Mexican beach pebble. To learn how we can help you enhance the character and beauty of your outdoor space, call us today.