Fossil

Fossils are generated out of pure-bone blocks with a structural integrity of 0.9%, this means that 10% of the blocks are replaced by structure voids leaving 90% as bone blocks. Coal fossils are also generated but they have the structural integrity of 0.1% causing 90% of the blocks to be structural voids leaving 10% of blocks as coal blocks, so the resulting combination of both generations combines and makes an incomplete fossil composed of bone blocks, coal, and structural voids.

Naturally-generated fossils are composed of a mix of both bones and coal blocks. There are 4 different types of skulls and 4 spines. They can sometimes even generate in the nether in soul sand valleys. The fossil is not limited by the Y level causing it to generate at any depth as long as it is underground.

Fossils are a great source of bone block for players that play on the peaceful difficulty. Other than that, fossils don't serve any gameplay purposes but do help in increasing immersion and a sort of mystery to the game.

Q. How rare is a fossil in Minecraft?

A. Fossils have a 1/64 chance to generate in a chunk.

Q. What can you use fossils for in Minecraft?

A. Fossils can be used to generate coal and bone meal for the player.

Q. Are fossils rare in the nether?

A. Fossils spawn quite frequently in the nether mostly in the soul sand valley biome.