Sturdy Fossils are used to make the 化石盔甲, 骨投刀, 琥珀法杖, and 骨头标枪. Sturdy Fossils are made by putting 沙漠化石s in the 提炼机, with about a 13.8% chance of acquiring a Sturdy Fossil from one Desert Fossil on average. It requires at least a 死亡使者镐 or a 梦魇镐 to mine. Sturdy Fossils can also be obtained from 蛇蜥怪s once in 困难模式. You need a total of 75 Sturdy Fossils to craft a complete set of 化石盔甲, which is the best Throwing armor currently in the game.
Placed Sturdy Fossils sparkle when an ore detecting item is used. Placed Sturdy Fossils also show up when a 金属探测器 is used, even though they do not spawn naturally.