In Evanston there was a rock shop Called "Dave's Down to Earth
Rock Shop", that carried some things. I spent all my spare change
there in college. I think it's still there. There's some
Evanstonians on list: perhaps they know.
Yes, Dave's is still there and going strong (closed on Wednesday and
Sunday). He carries wire, sheet, sawblades, some tools, rough, and a
wonderful variety of reasonably-priced stones, especially cabs.
Friendly, helpful staff. Various organizations get a discount (10%,
I think) including the Evanston Art Center, but I suspect that
almost any affiliation you mention will do, as will a resale number.
This is one of those local businesses I'm delighted to support.
I'm told that Tom Thumb, a hobby shop in Evanston, also carries
sheet and wire plus findings, and many beads. Plus Chelsea's Beads
in Highland Park, though I haven't been there.
Whether any of them have things like etching mordant or liver of
sulfur I don't know. Dave's seems the best shot.