From Wikipedia on bones:

Bone matrix is 90 to 95% composed of elastic collagen fibers, also known as ossein,[5] and the remainder is ground substance.[6] The elasticity of collagen improves fracture resistance.[7] The matrix is hardened by the binding of inorganic mineral salt, calcium phosphate, in a chemical arrangement known as bone mineral, a form of calcium apatite.[9]

So the statement is a bit faulty, not only because of the relative low amount of calcium in our bones, but also because it appears as a mineral. We distinguish between salts and metals because of their chemical properties being quite different (solubility, reflectiveness, electrical conductivity, maleability and so on).

Edit: I do realize the point of the comment was not to be entirely factual, so if I am allowed as well I would say science is pretty metal.