Garrett424,
I'm from Maryland myself. I grew up on the Susquehanna River. There are some neat specimens there too and a lot of Native American artifacts. Look for Serpentine, it's everywhere. Floods will bring everything to the surface. Do you have a photo of the Quartz crystal you found? I'd love to see it.
I don't have a pic yet but I can shoot one easily enough. I'll try and get that up soon.
I'm near the upper Patapsco near Woodstock and below Marriottsville, about 3 miles upstream from the last remaining dam at Daniels. I grew up about a half mile from the river and spent as much time as I could near the river growing up. I swam, hiked, fished, hiked, camped, went canoeing, Kayaking, tubing, inflatable rafting, you name it. I still do most of those things but this year metal detecting has been my new obsession.
I still go down there regularly and all over the area ALL the time during the warm season. I was there two nights ago.
I just love that whole valley and I know every trail, stream, etc. Being out in the woods does my soul more good than any shrink could ever begin to do.
Once you hit Ellicott City (going downstream) it's still nice but not the same. It's still pretty pristine where I am for the most part. Gettin' a little too well known though. People are beginning to really trash some once beautiful spots and it just disgusts me.
As for the Susquehanna; forget about it. That's one awesome river. I've long heard that you can still find Indian relics up that way but I've never hunted the area. I need to get up there.
The Susquehannock tribe was obviously big in that area, not to mention far to the North as well as the South. It's a shame but they were completely wiped out. The last small group were all murdered.
They, as well as the Piscataway and a few lesser known tribes hunted my area but had no settlements. No tribe did. It was basically unclaimed but used by several different tribes in different seasons, hence the rarity of any relics. When I found my hand ax least year I almost had a heart attack. It took me over 40 years for me to find that piece. It's pretty eroded because it was in a stream bed buried in rocky mud for who knows how long but to me it's incredible. My son thought it was just another rock when I showed it to him. He wasn't too excited but he loved the fossil I found around the same time.
I also know of a cave that was used for centuries as a hunting camp by many Indians. One guy, a self proclaimed "Indian" who lived the native lifestyle, did an amateur archeological dig back in 1960 and found a few projectile points and pottery pieces. He claimed to know of six more spots but took the locations to his grave. I have a hunch I know where at least one is but I've never really hunted the spot. I just never realized where I was. I'm gonna' try to hike in there before it gets too cold. It's maybe an hour hike one way.
I also found a pretty cool stone core fossil last year as well. I actually posted it here to get it identified a while back. I think that one could be millions of years old. It wasn't far from an old granite quarry long since closed and filled with water.
The town of Granite (which is no longer a town by any stretch), where I grew up was a quarry town and my grandfather on my dad's side was a stone cutter.
So, I can definitely relate to you picking up all of those rocks. I've been doing it for a very long time myself. It's way more work than most realize, not to mention the miles and miles and miles of walking, wading and stomping through God knows what.
That's one reason I love metal detecting so much. I always find something be it junk or something really cool. The gratification is way faster and far more frequent.
I still like my rocks though.
Groovy TN & KY agates! 
Andi
