It's commonly confused about what the rarest color of an item is. I'll use top hats as an example for this post.
People usually grade item color's rarity by their popularity. Popularity doesn't actually make an item "rarer".
This is the order of the rarity of each color top hat that is commonly used (I did not include founders or freedom hat)
So why exactly is the pink top thought of as the least rarest?
For one thing, pink is the originally color they came in.
Yes, that is a low quality picture, but that doesn't matter in this case. :P
One reason why the main color it came in when it was sold, was because people bought the first color just to try it on and see what it would look like. But is pink really the least rarest, or is it a misunderstanding?
You can't judge something rarity just because you see it a lot/not a lot. Just because you see one color a lot, doesn't mean there aren't a lot of another color. Some days I see a lot of brown top hats, some days I see a lot of black top hats, some days I hardly see any top hats at all. But if I were to judge on how many of that color I usually see, this would be the order:
See? Much different results. So why exactly is dark blue though of as the rarest?
I'd say because a lot of people think it's the coolest.
But what color really is the rarest? Well, it depends;
I depends on what way you look at it, and what you think is the rarest.
Everyone has different opinions. ;)