How Fire Glass is Made

Find out what makes fire glass safe to use in a fire pit or fireplace.


Many homeowners and interior designers have recently discovered the beauty of fire glass. Gorgeous in both indoor and outdoor fire pits and fireplaces, fire glass has an effect all its own. There are a variety of methods used to make the different shapes of fire glass. However, all types of fire glass go through a process called tempering.

So, what is tempered glass? How is it different from other glass?

Well, it’s all about how the hot glass is cooled. Tempered glass is rapidly cooled or “quenched” by a blast of high-pressure air.

Here’s what happens to glass during quenching:

The instant cooling causes the outer edges of the glass to decrease in temperature much more quickly than the inside. The exterior surfaces of the glass compress quickly, while the interior of the glass pulls away from them in a state of tension. This combination of tension and compression produces glass that is four to five times stronger than regular glass.

If tempered glass is quenched, how is regular glass cooled?

Regular glass, like the kind you might find in a window or in a glass bottle, has not been fully tempered. This material is typically made of “annealed” glass. In contrast to the instant cooling of tempered glass, the annealing process is a slower cooling process. While this technique does help strengthen the glass and makes it less likely to crack or break, it doesn’t produce glass that is safe for use in a fire.

After fire glass is tempered, it is safe to install in a fire pit or fireplace. The heat won’t cause it to crack or pop, and it will even retain and radiate some of that heat.

How are the different shapes and types of fire glass made?


You may have noticed there are a lot of choices when it comes to fire glass styles. Here’s a little more about them and how they are manufactured:


  • Original fire glass is made by shattering a large, flat piece of tempered glass. Like other safety glass, it will naturally break into tiny pieces that are all of a similar size.
  • Crushed fire glass is literally that – crushed and allowed to break apart naturally. As a result, you’ll see some attractively organic curves and lines.
  • Fire glass beads are carefully shaped into rounded drops. This creates a uniform fire glass appearance and a very stylish, modern look.
  • Fire glass dots are the smallest pieces typically used for fire glass. The rough edges have been rounded out by tumbling the glass, yet each piece has a unique shape to add interest.
  • Fire glass diamonds create perhaps the boldest design statement. Formed in molds, these triangular, three-dimensional shapes will stand out in your fire pit.


Each of these fire glass styles is distinct and is made in a slightly different way. However, they have all been tempered to make them safe to use in a fire. Which one you choose is completely up to you! Pick one that appeals to you or that matches your décor, and enjoy your fire glass!

If you’d like to learn more about these different fire glass looks, download our eBook on all the types of fire glass. Various sizes, shapes and colors are available to match any décor and to suit any taste:

Free eBook: Guide to Fire Glass