I'm sure Chris will respond, but I'll take a crack at it. I used to do reproduction 18th-Century blacksmithing, including making firesteels, and I've worked with flintlocks quite a bit.<br><br>Iron pyrites (fool's gold) is useable without a steel-with a lot of practice. There may be other minerals that work as well, but I haven't heard about them.<br><br>The trick here is the length of time that a spark lives. When striking flint against a firesteel, you're actually shaving off microscopic bits of the steel that become white hot from the friction of the strike, and persist for a second or two- that's why, with traditional flint-and-steel, the steel is critical, but the flint less so- you can use obsidion, quartz, even broken glass- anything with a sharp edge that's considerably harder than the steel itself.<br><br>Even so, preparation of the tinder is critical, and most of the people who use flint and steel prepare charcloth, or bracket fungi, or whatever by charring it in high heat with reduced oxygen- this makes a charred substance much more liable to hold and nurture a brief spark that even dryer lint, but it only smoulders, even when blown on- you need another "stage" of tinder to work it into a flame.<br><br>It does take practice. I used to keep in practice by using a flint and steel instead of matches to light the wood stove every time, all winter. There are a lot of folks who are better at it than I am.<br><br>In striking quartz together, I'm not even sure you're getting the same type of spark- instead of superheated microscopic bits, you might actually be generating electrical sparks via the piezo effect that quartz is known for- which would be of such short duration as to make it almost impossible to kindle anything much more solid than a flammable gas or vapor.<br><br>None of this is particularly relevant to using the new "artificial flints", which work on a different principle (shavings of the "flint" ignite instead of the steel), and, especially with magnesium, are much, much less touchy about the tinder. With the "primitive" methods, the steel is important- but as long as it sparks, the tinder is the real key.<br><br>