Technically speaking, red diamonds are diamonds, but they serve to highlight the fact that that diamonds actually come in a range of colors. They are, in order of rarity: yellow, brown, colorless, blue, green, black, pink, orange, purple and red. In other words, The clear diamonds you’re liable to encounter at your local jeweler aren’t even rare as far as diamonds go.
As a point of reference, the largest red diamond on Earth —The Moussaieff Red, pictured here — weighs just 5.11 carats (about 1 gram). The largest traditional diamonds — such as those cut from the 3,106.75-carat Cullinan diamond — weigh in at well over 500 carats. [Photo Credit: The Gemological Institute of America]