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Learning Center - Types of Fire Pit Media

Lava rocks, fire glass, and river stones: everything you need to know about fire pit media that will bring your fire pit aesthetics to the next level.


If you own a gas fire pit and are looking for alternatives to traditional wood logs, you’ll probably be searching for fire pit media. Media refers to materials that replace logs but still help create a flame appearance. While these additions to your fire pit might seem like purely an aesthetic choice, they serve a handful of purposes as well.

For anyone who has looked into a gas fire pit burner, it appears all the flames are focused on one area, the spot where the gas exits the burner. Once media is added, the flames are distributed more evenly and help create a much more realistic flame. Media helps distribute gas flow from the burner to make the pattern more natural in appearance, while also hiding the pan, burners, and fireplace gas valve as a bonus.

Examples of fire pit media include fire glass, lava rock, ceramic gas logs, river rocks, and fireballs. Don’t be fooled, don’t use river rocks collected from your backyard, or local river. These stones are likely to contain water, absorbed from the outdoors, and will produce a build-up of steam once heated up. This will damage your fire pit and cause the stones to explode.



Whatever media you use should cover your burner only about one inch in-depth, if you have proper gas pressure calibrated in your system. However, your media’s placement may vary from burner to burner. It’s recommended, as always, that you check your owner’s manual to ensure the correct depth and amount of media to use.

For example, referring to the manual is helpful is if you will be adding media to burners with raised jets. In this situation, you’ll want to leave the jets exposed, while covering up the burner tubes. It’s up to your discretion (after reading the owner’s manual) of how much you want the burner jets to stick out above, or in line with, the media, but make sure it doesn’t obstruct your fire pit from functioning properly.



Naturally formed from volcanic magma, lava rock is a natural and organic material. Their recognizable porous look is created from the cooling of hot magma. When trapped gases burst through the surface of the cooling magma, it leaves behind pockets, and voila, a porous lava rock. Their volcanic composition is what makes these rocks guaranteed fire-safe. Their origins make them durable when exposed to extremely high temperatures and as an added bonus they are completely maintenance-free.

Its unique composition makes lava rock a naturally beautiful filler for your fire pit, but also as a base for more expensive fire pit media. Mixing and matching your media can ultimately save you money.

Lava rock varies in size, shape, and color due to its natural formation, therefore each batch you purchase will be slightly different. Those looking for a uniform look should buy lava rock in bulk up-front to avoid too much mixing of colors or size. But others who may be interested in getting a natural, mix-matched look, need not worry about this and can purchase this readily available material as needed.



First, it’s recommended to use a sturdy pair of outdoor gloves while handling lava rock.

Once you’ve purchased your batch of lava rock, pour the media onto the ground to remove dust and broken pieces. Dust can clog burner ports and prevent your burner from functioning properly.

Instead of dumping large quantities of lava rock onto your burner at once, place individual pieces for a more uniform look, so you won’t damage any of the burners with a hit from rambunctious lava rock. Begin with small pieces to create the first layer and then build your way up with larger pieces on top.

If you’re interested in mixing lava rock with more expensive media, follow the same process but fill the burner only three-quarters of the way up. The top layer will then be your choice of fire glass or river rocks.



Lava rock will absorb any liquids, including rainwater because of its porous nature. If your lava rock is exposed to liquids, the first thing to do is NOT turn your fireplace on high. Although this may cause the water in your lock to boil and evaporate, it can also lead to them bursting. It’s recommended that you turn your gas fire pit valve on low for about 15-30 minutes, which will safely steam off excess water. The time this takes may vary depending on how humid of a climate you live in. Once your lava rock appears to be fully dry, gradually increase your heat.

An easy way to prevent your lava rocks from getting wet is to keep the fire pit covered! Doing so will prevent damage caused by the elements and weather conditions. If your fire pit comes with a warranty, not using a cover can cause your warranty to be voided. However, it is essential that you wait for your gas fire pit to completely cool before covering it. Placing a cover on a hot fire pit can cause it to melt and ruin the burner.



Fire glass is tempered glass that is commonly used as gas fire pit media. The process of tempering glass makes it more durable when exposed to high heat. The process can be achieved through either a physical heating process or through a chemical process. But ultimately the process creates glass that is four times as strong as un-tempered glass. A positive about fire glass is it comes in a wide variety of colors.

Once the strengthening process is complete, fire glass is tumbled to remove jagged edges. The final product is specifically made to withstand intense heat and will never discolor, melt, burn when exposed to a gas fire. Nor will it produce harmful byproducts like soot, ash, or smoke if used correctly. Never use un-tempered glass in your fire. Because it has not been strengthened in the tempering process there is risk it will explode and send broken glass flying.

A major bonus to using fire glass is that it produces about 3-4 times more heat than lava rock and gas log installations. This media’s shiny reflective surface is not only a stylish choice but incredibly efficient.



This fire pit media comes in small, medium, and large sizes, as well as a wide range of colors, as previously mentioned. Size and shape is not uniform, and batches will often have a bit of a mix between small, medium, and large sizes. This makes it easier to purchase different batches at different times, and not have a stark difference between the two batches. Shoppers can also choose between reflective, accent or smooth glass for their gas pit media.



This style of fire glass is formed by chipping small glass pieces off large glass bricks before being tumbled to remove jagged edges. Because of this process, no two pieces will be the same shape. In regards to usage, it’s best to place these pieces on top of large fire glass chunks, rather than filing your entire burner with this media. Choose a single color to accent you’re aesthetic, or pick two or three colors to create a fun colorful look.



These shards of fire glass have a mirror-like finish that makes them instantly appealing to gaze at. Furthermore, this media has the most intense color. Your fire pit’s flames reflect off these mirror-like shards to create a stunning visual, regardless of the time of day.



These small and non-uniform pieces of fire glass come polished for smooth edges. They are a similar shape Milk Duds or Junior Mint candies. Coloring is consistent throughout a batch and the glass is noticeably translucent.



Fire glass is the pricier option when compared to natural lava rock, especially when you are thinking of filling up a deep fire pit base. While using lava rock as a base layer is an economic move, fire glass will still work as a foundation for your burner. However, those who opt for a lava rock base layer should be aware of soot build-up on their fire glass top layer. You can avoid a sooty appearance by choosing dark-colored fire glass instead. If you are set on using a lava rock base and a light-colored fire glass, you must frequently clean off the soot build-up on the fire glass layer.

If cleaning your fire glass doesn’t sound appealing, there is the option to buy a cheap variety of fire glass as a base layer, and use colored glass as the top layer. Lava rock will still be the most cost-efficient option, but this is a nice compromise between convince and cost.



Although fire glass is durable, it still can break. Place your fire glass in a bucket of soapy water. Make sure to wear gloves to protect your hands from any broken or chipped glass. Next rinse your glass and lay it on a towel to air dry. Makes sure the fire glass dries completely to avoid getting unnecessary moisture into your fire pit that could cause problems.



  • This may seem like an obvious tip but it warrants reminding, always handle media once it has completely cooled. Keep in mind the bottom layers of your media will remain hot for long after you’ve turned off the fireplace gas valve.
  • Never use fire glass or lava rock with a wood-burning fire! They are perfect for your propane or natural gas fires, but keep them out of your wood campfires.
  • Fire glass must be the top layer of the only media in your burner. Do not place lava rock or other media on top of fire glass. This will cause damage to the fire glass and your burner and quite frankly, will not look as nice.
  • Soot is never caused by the media in your pit. In fact, this is probably a sign that something is wrong with your air mixture. If you notice excessive soot build-up, contact your installer to check if heat build-up or ventilation are properly working. If you still can’t find an issue it may be time to get an inspection of your fire pit.
  • Always keep proper ventilation on both sides of your fire pit. Despite fire glass's ability to resist high temperatures, if too much heat is trapped inside the unit, you create a potential risk for fire glass to crack or melt.
  • Remember that fire glass can still crack like any glass! If dropped, jagged edges can form and create a risk for injury. The main safety tip for handling fire pit media is to wear gloves to prevent cuts, burns, or other injuries.


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