I came upon Torin's quarry by accident, and there was this huge ass boulder my companions kept picking up, so I took it away, dropped in the wilderness and ran away before they picked up again.

Turns up it was a quest item, and since I dropped it in the wilderness...I'm screwed out of all blessings, am I not? :(

I'm reasonably certain you're S.O.L. My condolences.

That sucks. I don't think you're gonna find a workaround for that. For future reference though here's a quick tip. You can drag questionable items into one of your 10 hot-key spots along the bottom of your screen. Quest items tend to have a distinct red seal if I remember correctly, but you can compare to a known quest item to be sure.

Eh, I'll bet you could edit your save game to add it to your inventory. "Oh look, I found another rock there, good..." Just make sure you have the right one, I imagine.
This seems petty enough to be worth an edit. Just back up your save first. I'm reasonably certain I've seen non-quest items with red seals. That said, this thing is... how many Stone of weight? The space savings for putting it in your quick item slot is worth it only if you can actually carry the dang thing around.
In general, though, this is a very important tip.

Yep, I think a shovel has red seal for one. And the stone definitely weighed a wee too much for my STR 7 character.

Actually, if you somehow disposed of every shovel in the game I'm not sure you could advance the plot eventually.

I gotta say I don't think you're right about the red seal, but I could be wrong. I'm going to check it out tonight to be sure so that we all know though. I believe that the shovel is a quest item because it's necessary to complete a grave-digging mission, but again, I could be wrong.

As for the stone's weight; that's a good point. I tend to play/build strong characters and Sogg Mead Mug is often the first companion I pick up (besides Virgil) who happens to be very strong.

Also, for future reference, if you find any item at all guarded by about a dozen harder-than-usual to kill creatures, you can usually assume that it's somewhat important. ;)

I tried with boulders in Ashbury, didn't work. Seems like you need exactly that one.

something slightly related: anyone ever throw a boulder at an enemy? i am curious about whether or not the added weight would do some major damage.