Answer: Calcium
In its pure form, calcium is a dull gray-colored alkaline metal that looks more like leftover pieces of a futuristic robot than the kind of white mineral-like substance most of us envision when we’re slugging back glasses of milk in an effort to build strong bones.
It’s also the most abundant metal in the human body, found both in ionic form (necessary for physiological and biochemical processes) and in its more familiar bones and teeth form as hydroxyapatite—the mineral form of calcium that comprises 70 percent of the weight of our bones and a significant amount of our teeth.
Calcium is so abundant in the human body, in fact, that almost all of the ash remains from a cremation are calcium-based, like calcium phosphate.