this mod is what i use to duplicate dianonds (for now in the leats ) what i mean by that is i am not done. any way this mod adds in a furnace witch the crafting recipe isn't working but you use that to get a diamond plate or you could put a diamond in a furnace. these diamond plates can be put in to a crafting table to get TWO Diamonds out of it. (just an fyi i am still working on this mod so stay tunned for updates.
You can find the recipes and pictures here
Mod page: http://mrfunn1.wix.com/minecool-gameing#!diamond-plate-mod/kh6g2
Thank you for downloading my mod here is
my website: http://mrfunn1.wix.com/minecool-gameing
on the mod page is whare you can find recipes...