From 30 Pharaon japanese quails,100 days of age with a weight of 245 g, we collected 184 eggs which were deposited at peak phase of the laying period. These eggs were weighed, measured and broken to separate the mineral shell from the rest of egg content. Eggs shell was dried and weighed. We used a caliper to measure its thickness in 3 areas of the egg (base, middle, top). By calculation we determined: shell proportion and index, density and volume. We also determined the primary chemical composition of shell and its content in calcium, phosphorus and magnesium. We obtained the following results: an average weight of the shell of 0,800 g, representing 6,768% of egg weight. Average shell surface was 25,607 cm2 and the shell index had a value of 31,251 mg/cm2. Shell thickness was 153,39 μm, at the bottom of the egg; 161,39 μm, at the middle of the egg; 172,64 μm, at the top of the egg and of 162,476 μm, as an average of entire egg. The shell density of these eggs had an average value of 1,951 g/cm3 and its volume was 0,416 cm3. This shell contains 1,87% water; 98,13% DM; 87,73% minerals; 10,40% organic matters, represented by 10,05% proteins and a carbohydrate content, in proportion of 0,35%. The calcium content was 1777,5 mg/kg, the phosphorus content was 90 mg/kg and that of magnesium had a value of 21,5 mg/kg.