This means some recipes are naturally exclusive to certain item types which can fit inside with the required materials.
The Cube can be used to condense the power of Runes and Gems into their stronger counterparts. The recipes listed below can greatly empower anyone from the beginning of Act 2 in Normal, all the way to the super end game. Using specific combinations of items you'll find along your travels you can create wondrous Crafted Items, repair and recharge your gear, and combine necessary quest items into their legendary artifacts. The Horadric Cube is a relic of a bygone era that allows for amazing transmutations to create items of your wildest dreams.
'You have quite a treasure there in that Horadric Cube.' - Deckard Cain