Fossils aren't bone. They're mineral deposits in the space the bone used to be. In rare cases there might be some original tissue but for the most part fossils

Fossils aren't bone. They're mineral deposits in the space the bone used to be. In rare cases there might be some original tissue but for the most part fossils are formed from sediment(?) infill. Preserved bones are...bones and not fossils. Think of fossilization like lost-wax casting.