User blog comment:Scalec/Rocky Thinking/@comment-26382736-20160122110227

I think simplicity would be good, but it has to be an extremely rare effect in order to give it substance.

Making people greedy could be a good side effect. How about for the main one you give the stone powers to heal or give incredible strength?

I'm just thinking of Pete's Dragon. Would boiling the stone and drinking the tea make you invincible? Would swallowing the thing make you immortal? Have fun with it.