Kriesten K, Egge H, Faust R
Experientia. 1979 Aug 15;35(8):1032-3. doi: 10.1007/BF01949923.
The egg shell (with cuticle) of the ostrich contained a total lipid concentration of 0.19 mg/g egg shell; the phospholipids constituted the major portion, among the neutral' lipids cholesterol esters, cholesterol and free fatty acids were identified. The egg shell lipids showed a stimulating effect on the crystal growth of calcium carbonate; the highest rate of crystal growth was observed with the phospholipid fraction.