Went to your site, great terrain!
I too, use rocks as rocks, and play M&T for AWI.
I've broken down my rocks into colors.
For AWI, the brownstone ("red' sandstone) of where I live-NJ.
For Pig Wars (dark ages) I use grey schist, also from NJ, but
typically the big ridge lines.
For cowboys, tan stones from Montauk (a place that has just
about any color rock you could want).
Now I have buckets of each.
The guys I game with now tease me by saying things like: "Your rocks look sooo real".
As indeed they do. And so do yours.