Most rocks are harder than bones, one example is a bedrock.
Bones are hard connective tissue, made up of bone cells, fat cells, and blood vessels, as well as nonliving materials, including water and minerals. Some bones have a very hard, heavy outer layer made out of compact bone. Under this layer is a lighter layer called spongy bone, which is located inside the end, or head, of a long bone.
Bones are extraordinarily strong — ounce for ounce, bone is stronger than steel, since a bar of steel of comparable size would weigh four or five times as much. As per Livescience.com, a cubic inch of bone can in principle bear a load of 19,000 lbs. (8,626 kg) or more — roughly the weight of five standard pickup trucks — making it about four times as strong as concrete.
There is no single hard-and-fast rule for distinguishing rock from bone, but there are a few principles that can definitely help you tell the difference.