Refine items are used in the construction of more difficult to obtain items, requiring large amounts of a particular resource. For example, to gain anything that requires four Boards, the player must collect 16 Logs. Six items fall under the Refine category, or 11 in the Shipwrecked DLC. Refine Items are generally used in Tier Two recipes, such as the Alchemy Engine. Purple Gems and Nightmare Fuel are often used in the Magic recipes, such as the Shadow Manipulator. The Refine tab is not automatically unlocked at the beginning of the game but is acquired through a Science Machine.