Are there only four minerals in the body?

No. Apatite-like mineral forms the mineral component of bones and teeth, while human inner-ear otoconia consist mainly of calcite. But this does not mean the whole body contains “only four” minerals. The body contains many chemical elements and mineral phases; composition differs by tissue and may include pathological deposits such as stones. I found no reliable support that apatite, aragonite, calcite, and cristobalite are a complete list of normal minerals in the human body.