A century eggs is a Chinese delicacy that consists of an egg that has been preserved over a period of several weeks or months. Though the name implies that these eggs cure for many years, the process actually takes much less time.
After they are fully cured, century eggs have translucent brown whites and greenish-gray yolks. They are also called pidan, hundred-year egg or preserved egg. While a century egg takes on an aged appearance, the color comes from the ingredients used in the preservation process. Unless the eggs are otherwise tainted, they are safe to eat.