GANGGREEN
45 Cal.
This is entirely anecdotal, but I gathered some whitish flint in the Flint Ridge area of Ohio. I don't know if that's technically chert or not. I was told that I should heat treat it, so I did in a turkey roaster filled with sand at 450 degrees for 8 or 10 hours, then slowly backed it down for several more hours. I don't know what I'm doing as far as making flints are concerned, but I was able to get one made in the proper size and that flint is as sparky as hell.