Fancy Diamond

"At certain times of the day the sky is colored. At sunrise you have what colors? Yellow, orange, and red. Suppose your diamonds take shape at these moments. They are reflecting the yellow or the red, and it becomes a part of them. Or if it is not sunrise or sunset, but the middle part of the day when the sky is blue, they reflect the blue. Just at the moment they turn hard they take on the color of the sky. if they are formed at night when there is no color for them they become pure and colorless, what we call white.
That is how it happens, I am sure."