I love how white the center stone is. I used to be a real snob about clarity, but now I would rather go down a notch in clarity to go up a notch in color.
The whiteness of the stone is due to its purity, and also to "brilliance." Brilliance is the amount of white light reflecting back and makes a diamond shine even in the lowest light. This is largely due to the depth proportions of the cut. If the cut is too deep or too shallow, the light will fall out the bottom or sides of the stone instead of coming out through the top. This stone is nicely proportioned and reflects back nearly all light.