Facts: The three natural occurring layers are different colors. The outer layer is the dark layer. The second layer going toward the center of the shell is turquoise and the innermost layer is white. The shell is around 1 mm thick although indigenous Australians say that northern eggs are thinner.The number of eggs varies with rainfall.The eggs are on average 134 by 89 millimetres (5.3 × 3.5 in) and weigh between 700 and 900 grams (1.5 and 2.0 lb),which is roughly equivalent to 10–12 chicken eggs in volume and weight. The first verified occurrence of genetically identical avian twins was demonstrated in the Emu. The egg surface is granulated and pale green. During the incubation period, the egg turns dark green, although if the egg never hatches, it will turn white from the bleaching effect of the sun.