Emerald and Obsidian Tools Mod 1.6.4
This is just a small mod i made that adds in emerald tools and armor, obsidian tools and armor, and the ability to smelt obsidian into ingots. Emeralds strength fits between iron and diamond, obsidian is stronger than diamond. All of the crafting recipes are the same as regular tools and armor.
Download here : http://www.5minecraft.net/emerald-and-obsidian-tools-mod/