Simple stones can be scavenged from any dirt or rough rock tile, the role sort of co-exists as immaterial herbalism.
I don't know man, those plants are physically manifested in the game. I'm not too fond of the infite source of "X" without it being defined by a biological cycle. And what skills would it use? Well how about none, I mean there are allready stones in adventurer mode, tough I'm not quite sure if you can find small rocks on tiles that were empty before (so... good...?!).
I already accounted for the points in your argument in my previous posts which i've, any forseeable way finding natural objects turns out it would still be nice to find objects like discarded sea-shells, amber, coral and other bits and bobs by searching every few months around areas, those stones don't nessecarily have to be accessible in fortress mode either, just contribution to the skill.
- Picking up rocks relies on the scavenger skill
- Rather than trawling the bottom of a river, you can simply pretend to pan for materials caught in the stream's current via a similar activity to fishing, and rooting around wet dirt for things washed up.
- The actual ability's success rate is determined by RnG and a minor timer between the last time it was searched blocking new spawns, with advancement in this skill for finding salvagable materials increasing your chances, to make it less renewable.
1 - New proposed skill
2 - Water flow moves small objects through rivers
3 - Natural displacement of dirt from rain/wind causes minor objects found to regenerate slowly over a course of months to elaborate further, if you find everything there is to find effectively, it will take longer to replenish.