Fancy color diamonds are recognized by the intensity of their color and their main (and in certain cases secondary) hue, all of which help determine their value.
Each color results from the stone’s specific chemical or structural properties. In certain diamonds, finely dispersed nitrogen atoms will produce different colors ranging from yellow to brown (daffodil, canary, cognac) depending on their quantity.
Traces of boron entrapped in the diamond’s structure give a blue color.
Green diamonds are believed to have been exposed to radioactive radiation while in the ground.
Pink diamonds are thought to result from a micro-dislocation in the lattice structure. The greater the dislocation, the redder the diamond.
A diamond with inclusions will vary from gray to black, depending on the extent of these inclusions, although black diamonds are rarely recorded as fancy colors.