Updated project metadata. Gallus gallus avian eggshell is a biomineral composed of 95% of calcium carbonate on calcitic form and of 3.5% of an extracellular organic matrix (proteins, polysaccharides and proteoglycans). The calcification process occurred in the lumen of the uterus into the acellular uterine fluid, and is divided in three stages (initial, growth and terminal), where the concentration and the nature of proteins varies depending on stages. We have used mass spectrometry methodologies to identify and quantify proteins secreted into the uterine fluid proteins during the three stages of biomineralization.