Turtle Shell

Turtle Shells are a Hardmode crafting material that have a 1/17 (5.88%) chance of being dropped by Giant Tortoises in the Hardmode Jungle and Underground Jungle after Plantera is killed. '''Not true as of 1.3.0.5. Perhaps a bug, but Turtle Shells can currently be collected pre-Plantera, allowing for Turtle Armor before Spectre and Shroomite.'''

They are used solely to craft Turtle armor. Crafting all pieces requires a total of three Turtle Shells.