The Rarest Eye Colors and How They Occur
| Eye Color | Cause(s) |
| Black | An abundance of melanin |
| Red/Pink | Albinism and blood leaking into the iris |
| Amber | A little melanin with a large amount of lipochrome |
| Green | A little melanin, a bunch of lipochrome and Rayleigh scattering of light |
| Violet | Lack of pigment mixed with light reflecting off of red blood vessels |
| Heterochromia | Increased or decreased pigmentation in the iris |