GPW wrote:Where do you find Flint ??? .... No rocks around here.... (all mud)

I'm afraid that you're going to have to find a rock somewhere ...
"Flint" in this application is actually any durable edge which is significantly harder than the steel that you strike against it. The flint shaves a tiny piece of the metal away which oxidizes and makes the spark. There are crystals in some granite that are hard enough (perhaps a piece of broken countertop?) I would
try things that you already have, an old grinding stone (don't beat on one that will EVER get put back on a grinder), a piece of quartz, some glasses are hard/durable enough (antique glass electrical insulator). In my neck of the woods, the hard part is finding a suitable steel, obsidian can be found by looking down and taking a few steps. Tool steels seem to be too hard, I have the best luck with spring steel, mild steel needs heat treatment, but can work if properly prepared. Also, In my experience, it seems that the metal/stone combination is important to making it work. Some stones work with one steel while with another it doesn't do anything. If you use char cloth, even the
tiniest spark will work. Find a place out of sunlight to test, sometimes that spark is hard to see.