What to do with the odd keystone ON POKEMON DIMOND?
Use it on the broken stone tower on route 209. In order to use it, though, you must have met 32 REAL people in your game. If you have only one friend at the time then go in and out of their base underground and speak to them 32 times! To catch a second one, you need to use the other odd keystone! One located near berry masters house and one located in twinleaf town! Once you have 2, you can get a 3rd but you must find another odd keystone underground!