Sealed Notebook

A "sealed folder" is an uncraftable item, appearing as a blue-green packet. They are found in loot chests around the Overworld and other dimensions, and especially in the hidden chests of libraries. The only thing to do with them is to wield them and "use" (right-click) them, which turns them into a Collation folder containing pages.

If the business of symbol-collecting is compared to a trading-card game such as Magic or Pokemon, the sealed folders correspond to booster packs; each one will provide a fixed number of pages in all, with at least one "rare" or "very rare" symbol guaranteed.