Natural red diamonds are the rarest of all natural color diamonds, with less than ten stones produced per year in the entire world. Only a handful of red diamonds have ever received the grade of fancy red, which is the purest form of red diamonds. Instead they often have modifiers such as pink, purple and brown, giving mixed colors, which are however extremely rare, too. Unlike many other colors, where a mixed color can often be less expensive than a pure color, a brownish or purplish red can command almost as high prices as a fancy red, since the color red in itself is so extremely rare.

Read more about the origin of the color in natural red diamonds here.