坚固化石 are crafting materials used to make the Fossil armor, Bone Throwing Knife, Amber Staff, 甲虫炸弹 and Bone Javelin. Sturdy Fossils are obtained by putting Desert Fossils in the Extractinator, with a 10% chance of acquiring a Sturdy Fossil from each Desert Fossil. Sturdy Fossils can also be obtained from Basilisks once in Hardmode.
Placed Sturdy Fossils sparkle when an ore-detecting item is used. Placed Sturdy Fossils also show up when a Metal Detector is used, even though they do not spawn naturally.
- Sturdy Fossils have no sell value, so crafting them into Bone Throwing Knives is the best way to sell them. Selling Bone Throwing Knives yields 3 per Sturdy Fossil used. However, Scarab Bombs sell for more at a profit of 30 but if the player is buying bombs to craft them, it is better to craft the knives instead.
- Not counting the javelins or the throwing knives, making all of the fossil equipment requires 87 Sturdy Fossils for the PC version, and 102 for the mobile and console versions.
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