How to find flint and other sparking rocks to build a fire in a survival situation

This story was originally published on OFFGRID. Words by Patrick McCarthy.

With the aid of modern tools, starting a fire may seem like an easy task. Just whip out a trusty lighter and a few scraps of tinder, and if all goes according to plan, you’ll have a fire going in seconds.

If the lighter fails to do the trick, you’ve probably got a backup or two in your survival kit — stormproof matches, a ferro rod, or maybe even a camp stove with built-in ignition. However, if you were somehow separated from all these tools, would you still be able to start a fire?

This can make all the difference in a survival situation. Photo: Courtesy of OFFGRID

Primitive fire-making skills can be a life-saver in difficult circumstances because they enable you to get a campfire going with minimal gear. We’ve previously touched on the bow drill and other improvised fire-starters, but one other method to know is the flint and steel technique. Using nothing but a piece of high-carbon steel (such as the spine of your knife) and a sharp-edged hard rock, you can generate enough sparks to light a fire.

Unless you’ve made a habit of carrying a dedicated flint rock and steel striker, you’ll need to know how to find flint in the wild. It’s important to note that the “flint rock” you find is unlikely to be actual flint or a rock — it’ll probably be some other hard mineral, such as quartz, chert, or agate. However, the name doesn’t matter for the purpose of survival fire-starting. What matters is the stone’s hardness and its ability to form a sharp edge.

It’s quite simple if you know what to look for. Photo: Courtesy of OFFGRID

The image above shows several types of flint, chert, agate, and quartz, which can be purchased from Emberlit along with various steel striker pendants. For more info on these items, check out our fire-starter buyer’s guide from Issue 18 of our magazine.

In this video from Wilderness Outfitters, Dave Canterbury discusses the characteristics of a fire-starting flint rock. Essentially, it must be rated at approximately 7 on the Mohs scale of mineral hardness, or slightly softer than hardened steel. This can be checked by hitting the rock with a hammer stone, and checking if the stone chips and breaks away with a sharp edge.

Some sources of flint may be encapsulated in a discolored outer crust. Photo: Wikipedia/OFFGRID

Another method to find flint is to attempt to scratch glass with the rock’s edge — glass is a 5.5 on the Mohs scale, so flint should be able to scratch it without much resistance. The video below from Mike Reed Outdoors explains in greater detail:

Once you’ve found a source of natural flint or similar hard rock, it’s just a matter of striking a carbon steel item with quick grazing blows. With a little practice, this will generate reliable sparks. It may not be as quick and easy as pulling out a lighter, but it’s a great fall-back method for primitive survival.

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