Death and Burial: An animal or plant dies and gets buried quickly under layers of sediment like mud, sand, or soil. This burial protects it from decay and scavengers.

Decay and Mineralization: Over time, the soft parts of the dead organism decay, leaving behind only the hard parts like bones, shells, or teeth. Minerals from the surrounding sediment seep into these hard parts, gradually replacing the original material. This process is called mineralization.

Compression and Hardening: As more layers of sediment pile on top, the pressure from the weight above presses down on the buried remains. This pressure squeezes out water and air from the sediment, compacting it and turning it into rock. The minerals that replaced the original material harden, preserving the shape and structure of the organism.

Exposure and Discovery: Millions of years later, erosion or other geological processes may expose the fossilized remains. Scientists or fossil hunters discover these fossils by digging or when they naturally come to the surface due to weathering.