Black eyes are actually not a true eye color. What appears to be black is actually a very dark shade of brown.
While dark brown eyes are quite common, they're not considered rare. Brown eyes are the most prevalent color, with an estimated 45% of the U.S. population and nearly 80% of the global population having brown eyes.
The rarest eye color is green, with a frequency of less than 2% of the population. Other rare colors include blue, hazel, and amber.
Therefore, black eye color is not rare because it's simply a very dark brown.
