Bone tissue is characterized by its mineral structure, showing unique properties as mechanical resistance, toughness and elasticity. These are due to its composite nature of collagen (the most important constituent protein in the bone matrix), with hydroxyapatite crystals. The place of collagen in the organization and growth promotion of mineral bone tissue is still under study. In this paper an evaluation of the piezoelectric effect of collagen, using the biomimetic method and scanning electron microscopy, is presented. It was found that after 3.5 weeks of exposure, deformed collagen initiate the precipitation of , at the collagen fiber “holes”, but only on the compressed side. This precipitation process, completely cover the surface in 5 weeks of exposure to the Simulated Body Fluid (SBF). This confirms that the piezoelectric effect is a probable mechanism for apatite nucleation and that the collagen fiber “holes” are preferential sites, however they don’t promote nucleation by themselves. Thus Wolf’s Law seems to be dictated by piezoelectricity alone.