Diamond Gem

Diamond Gems are the hardest material and also a very precious gem.

Crafted from
1 Block of Diamond

Crafting Usage
Used to make Diamond Swords, Diamond Shovels, Diamond Pickaxes, Diamond Hoes, Diamond Axes, Blocks of Diamond, Diamond Helmets, Diamond Chestplates, Diamond Leggings, Diamond Boots, Jukeboxes, and Enchantment tables.

Pocket edition only
Used to make Nether Reactor Cores.

Usage
You can use them to make the highest tier sword AND at the same time second best weapon in the game, or just obtain money from them.