Question: why are green eyes so rare as only 6% of the world's population has them?

Remsha Afzal answered on 16 Nov 2018:

Very good question! So basically your eye color is a result of genetics (up to 16 genes), largely the pigmentation genes of the iris but also the way light scatters around the iris itself. Pigmentation of a person’s iris can run the darkest color, black brown to lightest, blue. Largely influencing pigmentation is something called melanin. Your question made me look further into the reason green eyes are formed and I found that “the appearance of green and shades of green (i.e. jade, hazel eyes and emerald) are the result of a  phenomenon known as Rayleigh scattering; which is a term used to describe the way light scatters after riding its spectrum wavelength”. So your eye color is a function of how light diffuses across the melanin base, which again is genetically determined