Can you please make it so that ores that are mines by silk touch pickaxes cannot be used as a protection stone?

Thank you.

You can use something like this: http://dev.bukkit.org/server-mods/changesilktouch

There is no difference between a mined item and a spawned item. If you want the stones to be limited (in the affect of unobtainable items) you need to find an unobtainable item id and use that as the pstone id
Example: "Id:125:0"