Monday, March 7, 2011

Why Does Pyrite Make a Spark?

Pyrite fire making set
Iron Pyrites were used by all of the pre-contact cultures in Newfoundland for fire starting.  There have been pyrite strikers found in the Maritime Archaic Indian burials at Port au Choix, in Palaeoeskimo sites across the Island and in Recent Indian contexts.  Even in Labrador, where the bow drill was used by the Inuit, iron pyrites were apparently prefered (Hawkes 1916:97).

Pyrite nodules
Striking a pyrite nodule against another piece of pyrite or chert might sound like an unusual way to make fire, but its basically the same method that a lighter uses to create a spark and start the liquid fuel burning.  The Vikings would have used flint and steel to start their fires 1000 years ago, and the earliest firearms in the Province were flintlock muskets that used percussion sparks to ignite the gunpowder charge.  Today, we're probably more familiar with matches and sparks from electric ignitions to start fires and fuel burning, but just a few hundred years ago, everyone would have been familiar with flint and steel, and probably pyrite, for starting fires.

Pea-sized pyrite in a chert biface
Pyrite, or iron disulphide (FeS2), is a brassy-yellow mineral that will oxidize to a brownish red.  Sometimes it is quite crumbly and friable, but the most useful form for fire-starting are solid nodules or angular lumps.  In Newfoundland, good pyrite nodules can be found on beaches on the Port au Port peninsula and can often be found in the same locations as chert.

Why Does Pyrite Make A Spark? When you strike a pyrite nodule with a sharp piece of chert, iron, or another pyrite nodule, tiny flecks of the pyrite are struck off and they instantly react with oxygen in the air, creating a hot spark.  You'll smell the sulphur burning.  If you direct these sparks into a flammable tinder you can ignite a glowing ember, which can be fanned into a flame to ignite tinder and build a fire.  In these photos I've used a bit of dryer lint. My pyrite nodules work fine for lighting fires, but they are several times larger than the pyrite fire starters that I've seen from archaeological sites.

Hold the pyrite with your fingers out of the way
Strike the pyrite with a sweeping, brushing motion (can you see the glowing sparks?)
You'll need a very flammable tinder to catch the spark, like this piece of dryer lint.

The pyrite fire starters that I'm familiar with from archaeological sites in the Province are about the size and shape of small, rust-coloured golf balls.  As they are used, the sharp edges and irregularities are worn off and they become more spherical or egg shaped.  They usually aren't too spectacular to look at, but they tend to get noticed in digs because of their weight.  Even under the dirt, you know that you are holding a chunk of metal and not an ordinary rock.

Pyrite fire starters (#5) illustrated in Howley 1915.  Image modified from the online version of the book.

Smoking tinder
If you want to know more about pyrite fire-starting - take a look at this page, which has good explanations, examples, and a how-to video clip: Paleolithic Stone on Stone Fire Technology.

Photo Credits:
1-6, 8: Tim Rast
7: Modified from:

Ernest William Hawkes, 1916. The Labrador Eskimo
James Patrick Howley, 1915. The Beothucks, or Red Indians, the Aboriginal Inhabitants of Newfoundland: The Aboriginal Inhabitants of Newfoundland


  1. I get better sparks with marcasite!

  2. Very interesting article! I never knew that pyrite was such a good fire starter. I'll have to go get me some and try it out! Thanks for posting this!


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