What gives bones strength and elasticity?

Mineral crystals are responsible for the hardness, stiffness and greater compressive strength of the bone, but they impart greater tensile weakness with other crystalline materials, arising from the tendency to concentrate on defects and their spread. On the other hand, collagen bone fibrils have high elasticity, low compressive strength, and significant internal tensile strength. The tensile strength of bone depends, however, not only on collagen, but also on the mineral’s bond with collagen, which gives the skin many of the general properties exhibited by biphasic materials.