Fire glass, lava rock, and how much you need.
Media hides the burner and pan and spreads the gas into a natural flame pattern. Getting the depth right matters more than getting the colour right.
- Products
- 5
- Price
- $50 – $85
Counted from this collection.
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Tempered, not decorativeRated for fire pits — it will not melt, discolour or smoke
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Depth guidance publishedCover the burner by no more than an inch
Use lava rock underneath.
Fire glass is the expensive part. Fill most of the depth with lava rock and lay the glass over the top, and you halve the amount of glass you need without changing what anyone sees.
The one exception is reflective glass, which should be the only layer on top — laying other media over it damages the display.
Glass or rock.
They do the same job. They cost very different amounts and they age differently.
- Fire glass
Never melts, never smokes
Tempered translucent glass. It does not burn, melt, discolour or produce smoke, and reflective varieties intensify the colour with a mirror finish. It is the most expensive option, which is why the lava rock base is worth doing.
- Lava rock
Porous, forgiving, cheap
Organic volcanic rock — fire-safe, weather-resistant and essentially maintenance free. Size and colour vary between batches, so buy what you need in one go if uniformity matters. Works as a base layer under glass.
How much, and how deep.
Too little media and you see the pan. Too much and you restrict the gas flow, which changes the flame and is the more expensive mistake.
| Burner type | Coverage | Why |
|---|---|---|
| Standard pan burner | Cover the burner by no more than 1″ | Deeper than that restricts the gas flow and changes the flame |
| Raised-jet burner | Cover the tube, leave the jets exposed | Burying the jets is what causes uneven or lazy flames |
| Lava rock base + glass | Rock to within 1–2″ of the top, glass over | Halves the glass needed with no visible difference |
| Reflective fire glass | Top layer only | Other media laid over it will damage the burning display |
General guidance. Always follow the volume and depth in your own burner's installation manual — it overrides anything here.
The questions we actually get.
Can I use rocks from my garden or a river?
No. Ordinary stones and river rocks hold moisture inside them. Heat that trapped water and it becomes steam with nowhere to go, which can make the stone burst.
Only media rated for fire pits — tempered fire glass or lava rock — belongs in a fire feature.
How much do I need?
It depends on the opening and the burner, so the honest answer is that your burner's installation manual gives the volume and we would rather work it out with you than sell you the wrong quantity.
As a rule the media should cover the burner by no more than an inch. Send us the burner model or the opening size and we will do the sum.
Can I mix glass and lava rock?
Yes, and it is the sensible way to buy. Lava rock underneath, glass on top — you see only the glass and you buy about half as much of it.
The exception is reflective glass, which should not have anything laid on top of it.
Does it need cleaning?
Fire glass collects soot over time and cleans up with a rinse every few months. Lava rock is essentially maintenance free.
The thing that actually shortens media life is water sitting in an uncovered pit over winter, which is what the covers are for.
Not sure how much to order?
Tell us the burner model or the opening size and we will work out the volume for you rather than leaving you to guess.
(307) 201-4597 9am–5pm MT, every day