Up for your consideration is a pontiled egg, ( size of egg, 1 7/8" X 2 5/8". ) I dug some 20 years ago from a old farm bottle dump. I was rather confused when it rolled out, I thought the old farm dump was pre- electric era, it looked just like the top of a old light bulb. Turns out it was a pontiled hen egg. These eggs had dual purposes, it was used by those darning clothing, as well as being placed under broody hens. No damage, cracks or chips. If you need more details feel free to write.