Minecraft wiki entry for Fossils, associated text: For most players, the primary use of fossils is as a source of bone blocks. This can be especially useful if playing on peaceful difficulty, as skeletons won't be able to spawn, meaning that bones are much harder to acquire. Fossils also generate coal ore, although if you want to find coal ore, it is much easier to just look in a cave. However, if you do come across a fossil and mine it for the bone blocks, it's worth it to mine the coal ore. Coal is very helpful, as it can be used to make torches, or used as fuel.