Portals

The Portal is the most useful item in the game.

Uses:

LV1

Workbench

Blockhead

Double-Time (2.99)

Time Crystals

Amethyst Upgrade

Warp in Copper or Tin

Amethyst Pickaxe

Sapphire Upgrade

Sapphire Pickaxe

Warp in 20 Iron Ore

Emerald Upgrade

Emerald Pickaxe

... See Portal Uses for more info