Here's a rare stone- and not only because it's been graded Fancy Light Gray by GIA.
It's also a really nicely cut marquise. Long and lean. There's a lot of sparkle for a gray diamond- which is also unusual. Bright flashes.
You can see the color, and still, it's pleasant.
In many cases gray, in diamonds, is not attractive - this one seems to pull it off IMO... sShow its gray color, and yet still be lively.