Jewel Prism

Jewel Prisms are items that spawn on the bottom of the Ocean once Skeletron and the Eater of Worlds or Brain of Cthulhu have been defeated. They come in four grades: Malformed, Small, Rare, and Gem Quality. Each kind is rarer than the last.

Use
Jewel Prisms can be put on weapons at the Jeweler. This boosts their stats by varying amounts. They are also used to craft Prismatic Armor.