These minerals form calcium phosphate, which crystallize on the cartilage framework, ultimately forming a bone matrix that's about one-third mineral, two-thirds protein.
When osteoblasts come in, they secrete a glue-like cocktail of collagen, as well as enzymes that absorb calcium, phosphate, and other minerals from the blood.
Sometimes, instead of oxalate, the calcium binds a negatively charged phosphate group to form calcium phosphate stones, which are dirty white in color and alsop radiopaque on an Xray.
From your time in the womb until you're about 25, your osteoblasts keep laying down more collagen and more calcium phosphate, until your bones are fully grown and completely hardened.
When they get there, they secrete both a collagen-digesting enzyme, and an acidic hydrogen-ion mixture that dissolves the calcium phosphate, releasing its components back into the blood. This tear-down process is called resorption.
Teeth manage both by having two layers: a hard external cap of enamel, made up almost entirely of a calcium phosphate, and beneath it, a tougher layer of dentin, partly formed from organic fibers that make it flexible.