What give our bones their white color?

Bones of the living body are not at all so dry, white and rigid, as we might think, seeing skeletons exposed in museums. Living bone is dark gray and is covered by a periosteum membrane, through which penetrate blood vessels and bones' nerves.

Although bones appear to be compact, in fact they are full of small cavities. Under the periosteum is following the compact tissue bone, Havers type.