Whether it’s a cold winter night or a starry summer evening, sitting around an outdoor fire has a timeless, sentimental charm. But it can still be improved. Adding colorful, shimmering fire glass to your fire pit creates a unique look and an unforgettable ambience. The sole purpose of fire glass is to provide a decorative boost to your fire pit.

Fire glass is regular glass that has become tempered, meaning it can withstand a high level of heat without melting, shattering, sparking, popping, smoking, or reacting in any other inconvenient or dangerous way. It’s tumbled to remove jagged edges as well as any stray pieces that would shard, cut, or puncture. Fire glass does not produce heat, but it does absorb and radiate it, and it doesn’t leave any ash or soot behind.

Despite its simplicity, fire glass still has some intriguing varieties and options, and there’s a lot to take in before you make a purchase. We’re here to guide you. 

Three factors come down to your personal preference: color, shape, and size. Shape and size are distinct choices, but as you will see, they play off one another. Another consideration, quantity, is purely for practical purposes.

As the main goal of fire glass is to set a look and tone, picking a color might be your hardest (yet most important) decision. There are a lot of options from which to choose. Varieties of blues, reds, greens, and purples are among the most popular, from cobalt and sapphire to ruby and emerald. You may opt for onyx black for an intense look or crystal for something that really shimmers. Amber, copper, and chestnut fire glass can create a rustic feel.

Some companies offer more color options than others, so don’t be afraid to search for the one that best fits your goal, whether it’s something old and natural, new and trendy, complementary and subtle, or simply bold.

Keep in mind that companies use different terms to describe the type or shape of fire glass they offer. There are no set definitions or agreed-upon terms. Here are a few common types, but be sure to look at the picture to really know what you’re getting.

• Beads or drops: These are the smoothest glass pieces. They are ovate or spherical without edges and can also be placed around a yard or patio to add a splash of color. Because all pieces are uniform, they look pristine, but they will not fill in gaps easily when piled up in a fire pit.
• Nuggets or diamonds: While these are smooth, they aren’t perfect ovals or spheres. They have a slightly more natural look in that they are not perfect shapes, and the irregularity means they can fill space more densely.
• Fragments or crushed ice: These resemble shards of glass, but they are still safe to handle and move around. The shapes are more random and tend to offer greater coverage, as they can be densely packed. Therefore, you need less of them to cover an area.

Fire glass varies in size, from a quarter of an inch across (small) to a full inch across (large). One-half inch is the most common size available. When considering size, keep the following in mind.

• Filling the fire pit: In general, the size of your fire glass should match the relative size of your fire pit. Large fire glass will overwhelm a smaller pit; smaller pieces won’t fill up a larger one easily. Companies recommend how much fire glass fits in your pit in terms of weight — usually in 10-pound increments. Keep in mind that small pieces will be more densely packed, so you will need more of them to effectively cover an area.
• Aesthetics: Bigger pieces may play a role outside the fire pit. For example, you might place them in a garden or along a walkway for decoration. Consider that if your fire pit is small, larger pieces may stand out too much. In a large pit, small pieces may look equally awkward.
• Heat: As a rule, smaller pieces radiate more heat than larger ones. This may help save a bit of energy. However, because you’re dealing with such high temperatures, the difference in heat emitted may not be noticeable.

How much fire glass you place in your fire pit is key to maintaining a successful fire. If you fill your fire pit with too much glass, the fire may be harder to control, and the heat could be unbearable if you’re close. However, if you put too few fire glass pieces in the pit, it will not be effective at generating extra heat or looking good.

Most companies recommend filling the fire pit with two to four inches of fire glass. Manufacturers specify on the bag how much of the product to use. Most bags have a handy chart to read, so be sure to measure your fire pit first.

Most bags come with a single color. However, there is the option in some cases of getting two or three colors mixed into the same bag. Unfortunately, the user doesn’t get to choose. If this bothers you, you could always buy two colors and mix them yourself.

Often, fire glass is used as an alternative to lava rocks, which create more fire combustion, offer a more natural look and feel, and generally cost less. However, the right fire glass looks great paired with lava rocks, and some companies have jumped on that opportunity. Just remember you’ll have to clean the glass afterwards, as lava rocks produce soot.

For those who want their fire glass to shine and shimmer even more, reflective glass offers just that. It is the same fire as glass, but it has been polished to such a degree that it really sparkles. It’s worth noting this is mostly marketing; fragment or nugget shaped glass, with their flat sides, should offer some sparkle, too. What’s more, you can always polish your glass at home for an extra pop.

Similar to reflective glass, accent glass is more marketing than design. Accent glass consists of potent colors that stand out on their own. It may be as much on the user as it is the company to determine what color exactly is an accent.

In general, fire glass is sold in 10-pound bags, though a 20-pound bag may also be an option. There is often a slight price break when buying larger quantities.

Inexpensive: Under $20, your choices will be slim, but you should find a few 10-pound bags, especially if you’re not picky about color or shape. Most likely, these will not be uniform pieces.

Mid-range: For $20 to $45, you’ll find a great many color, size, and shape options, from irregular pieces to drops and gems.

Expensive: In spending over $45, you will likely find fire glass that is uniform, giving off a modern, clean look as opposed to something more rustic. In this range, you will also find the 20-pound bag versions of the previous price points.

• Remember fire glass properties. A lot of companies laud their product as the best. Keep in mind, though, that all fire glass is tempered regardless of who makes it (provided they make it properly, of course), and it will not break, pop, melt, or produce ash or soot.
• Use natural gas over propane. While fire glass works fine with both types of fire pits, the latter may, over time, dampen the glow. Propane can produce a residue that may eventually adhere to the glass, which will lessen its luster and require more frequent cleaning.
• Know what your colors do. Browns and reds convey a rustic feel, while blacks and greys are minimalist and trendy. Greens and blues may evoke forests and lakes. Purples and reds tend to be bold.
• Match your tones, too. Darker tones are generally more understated and have a modern feel. Lighter tones can really shimmer and shine. The same color may have both lighter or darker options. Amber, for example, may be both rustic and glimmering.
• Mix colors! This was alluded to earlier, but if you have some money, time, and space to spare, it may be intriguing to purchase a couple different colors and combine them. The fire pit is your vision, so don’t be afraid to get creative.

If nothing else, Fire Pit Essentials offers an in-depth look at the possibilities of fire glass. Still, they feature reasonably priced fire glass in the shape of beads, dots, cubes, and diamonds, with a collection of glass in a wide range of colors with imaginative names, from Pine Mountain (greenish) to High Desert (red-like). Similarly, for a relatively low price, Golden Flame offers a handful of color options in angular half-inch glass, which is the most popular shape and size.

Q. How should I clean fire glass?
A. While the glass won’t create soot or ash, being outside means it might get dirty. Water and soap will do the trick, but even a quick rinse should suffice.

Q. How long does fire glass last?
A. Technically, fire glass will last indefinitely. However, the glass may be negatively affected by outside elements. It may lose color and shine over time, and wind, rain, or snow could damage the look as well.

Q. Does fire glass save energy?
A.  As fire glass channels heat from the flame and emits it at a higher temperature, you should be saving some energy as opposed to lighting a straight flame. Generally, you can keep your flame at a lower level when you have fire glass to produce the same amount of heat as you would with a higher flame without fire glass.