Buzz
A chicken egg forms its shell at the moment of its creation. The shells serve to protect the eggs. Jorn Georg Tomter / Getty ImagesKey Insights
- The shell of a chicken egg is produced by the egg itself, using layers of calcite (calcium carbonate) that fuse together.
- This process happens around a membrane, with uniform nucleation points where the calcite, suspended in solution, deposits and crystallizes to form the shell.
- Specialized protein nodules called mammillary protrusions act as the initial sites for the calcite to crystallize, forming the shell.
In a spectacular showcase of nature's extraordinary abilities, the egg is encased in an impeccably smooth, incredibly durable shell, almost as if created by magic! Eggs truly are masterpieces of nature.
It turns out the chicken has little involvement in the creation of an egg's shell -- instead, the egg itself actually grows the shell around it! This process mirrors those found in the formation of bones and seashells.
The egg is surrounded by a membrane, and along the membrane, evenly spaced sites where columns of calcite (a type of calcium carbonate) develop. These columns align side by side, forming the shell. An intriguing book called "Made to Measure" by Philip Ball explains this process:
The calcite essentially floats in a solution around the shell and deposits onto it, gradually forming a crystal-like structure. The egg grows its own shell in this remarkable way!
Explore these links to dive deeper:
- Understanding the Formation and Parts of the Egg
- Which came first, the chicken or the egg?
- What makes an egg carton claim that the eggs inside are lower in fat and higher in vitamin E?
- Why do eggs become firm when boiled?
