sorry i don't remember exactly where i got mine but where were you told to look? i might be able to give you an idea then....i passed that mission (and strangely still have a stone....) did you try digging under the blue flowers???? or lookng in a store in that area?(that's what got me on the one mission DX) try that and get back to me.... if you still can't find it...that is * checks date on post*
~Tora
Okami~