Natural Megalodon Fossil Tooth

The Megalodon (Otodus megalodon) was once one of the most fearsome predators to reign the seas. This ancient shark was roughly up to 3 times the length of a modern-day great white shark and it is the largest shark to have ever lived.

As sharks are cartilaginous fishes, with the main exceptions being teeth and dermal ossicles which are enameloid and vertebral centra.
As cartilage does not mineralize to the same extent as bone does, due to this it breaks down much quicker and easier than bony material. This is why teeth are the most common part of the shark that is fossilized.

The colour of the teeth is a result of the minerals that are present in the surrounding sediments. Teeth fossilize through a process called permineralization. Over time, seawater moves through the soil and rock around buried teeth. This water carries tiny minerals, which slowly seep into the pore spaces inside the tooth. As these minerals build up, they harden and turn the tooth into a fossil.

The colours of fossil teeth can vary depending on the minerals involved, different minerals turn different colors as they form and react with trace amounts of oxygen. For example, as iron oxidizes it begins to rust and typically turns a reddish brown. The same can happen to fossils.