Fancy Diamonds

How many different basic colors have been identified?

There are 12 basic color varieties, such as pink, blue, red, orange, purple, yellow and so on. But then these varieties can be modified by additional colors. It's a bit like mixing paint.
Add a little bit of one color and it changes subtly; add a lot, it changes more dramatically.
You end up with something like 60 individual colors based on the 12 varieties.
But then you have different "saturations", or hues, which means a diamond can be pale of blush, or of deep or medium saturation.
In the end there are probably hundreds of colors within the spectrum.

What is the rarest color?

Purple. There are very few in the world. Also, orange and violet. Yellow and brown are the most common.

Fluorescence in color diamonds?

Fluorescence in colorless diamonds has been considered a negative quality. But in colored diamonds it's an attribute, because it brings out a range of different expressions. A diamond's color in direct sunlight is different than in indirect light. The colors are different in incandescent light that they are under fluorescent light. A single colored diamond can undergo any number of personality changes.

Where do most of these stones come from?

A majority come from Africa. Except for the highly saturated pink, which come from Australia's Argyle Mine.
Those are a kind of strawberry or wine color, but they're generally small, only up to about four carat.
Also Australia's supply will be exhausted in ten years' time.

How do colored diamonds compare in price to colorless?

Colored diamonds in the brown family, often referred to as "champagne" or cognac", would be priced probably 10 to 50 present less than a fine quality white diamond. On the other hand, pinks and blues may be equal in value to a colorless diamond or perhaps ten times more. For example, if the average price for a perfect colorless five-carat diamond is $100,000 a carat, then the possible price for a rare, extraordinary colored diamond could be anywhere
from $500,000 a carat to $1 million or more.