Minium Stone

The Minium Stone is the main scoop of in its current state; it allows the player to exchange blocks in the world for other blocks of an equal "equivalence value". Other than that, the minium stone can be used as a pocket crafting table, by pressing "C" while it's in your hand. Crafting in the crafting grid does not cost any minium stone charge, if you do not use the minium stone in the grid.

The minium stone is also able to exchange items in a crafting grid - you can craft most metals into diamonds.

Furnace
The minium stone can be used as a slightly less efficient furnace. Put any 7 ores, 1 coal and the minium stone in a crafting grid, and it will give you 7 ingots or other processed items.

Transmutation
These are the first steps towards making Diamonds. You can craft 4 clay into a clay brick (and transmutate it back as well), and make Iron Ingots out of it, or use Obsidian.

You can also craft whole storage blocks into the next tier of storage blocks;

Crafting World Objects
Another thing you can do is transmute blocks you could transmute in the world, in a crafting grid;

All these recipes will work in the world as well.

Miscellaneous
These are some more recipes.

You can also exchange dyes and colored wool.