By Anna Zhang

Blue is the most abstract color on the color wheel. Not only is it the most popular color in 10 countries, it is also the rarest color in nature. 

Look outside your window—do you see any blue plants? Blue animals? 

Doubtful. 

This is because most things in nature that appear blue are not truly blue. 

With that being said: blueberries aren’t blue; they’re purple. The popular fruit, blueberries, uses anthocyanin—a purple and red pigment—to color itself.  

Pigments are substances that absorb light and reflect others to create a color. In nature, most blue hues are created by the mixing of other color pigments. But that doesn’t count as true blue. The only thing that can truly be counted as blue, is a natural blue pigment that isn’t modified. For example, red flowers use red pigments in the DNA while the morpho butterfly uses “interference” or “coherent scattering” to seem blue. The morpho butterfly’s iridescent mini scales reflect light and jumble them together to create something that looks blue to the human eye—but the morpho butterfly has no actual blue pigment in its DNA. 

Another example of this is that blue eyes aren’t blue either; they look blue because of a combination of scattered and merged light hitting the eye’s iris. The “blue” is actually colorless in the stroma – a thick tissue in the eye that is meant to contain collagen and melanin to color the eye. Because of this, blue eyes aren’t fixed. They can change based on the amount of light when you look at them. This is also why the sky appears blue!

The only flower to have a true blue pigment in them is a modified flower created in Japan. They managed to make a blue chrysanthemum by using the molecule delphinidin which was modified by combining various other color pigments. Attempts by other scientists trying to do the same thing resulted in violet flowers rather than blue ones. 

For the animal kingdom however, there is one blue creature. It’s the only exception though: the obrina olivewing. This butterfly is the only animal to ever contain natural true blue pigments. 

So as you can see, there is a very slim chance that you have seen real blue outside your window. Most blues are mixes of either purple or red, or or certain ways of reflecting light. None of them are true blue pigments.