A fossilized bone is simply called a fossil bone. When organic material in a bone is replaced by minerals over time, it undergoes a process called fossilization. This process transforms the bone into a rock-like substance, preserving its structure and some of its original characteristics. Fossil bones can provide important insights into past organisms, including their anatomy, evolutionary history, and behavior. Paleontologists study fossil bones to reconstruct ancient ecosystems, understand the diversity and distribution of extinct species, and unravel the history of life on Earth.