Somewhere between d and z.
Pictures appear different colors on different monitors so it is impossible to grade color going by a picture on a computer.
Far as that goes different film cameras will see color differently too and the same camera different film or developer process will appear to be different colors also.
Bottom-line anyone that says they can tell the color grade by seeing a photo is liar.
Perfect picture! Oh, and the model is not bad either.
Unfortunately, color cannot be guessed from computer monitors: this is a I-K on my laptop and a D-F on my desktop.
And this was said taking into account the hypothesis that the background of the pic is white, not the collection of grays and tans that make up the image of the stone...
Haha... this picture was taken under white hemisphere lighting so it is impossible to assess color, face up, under these conditions. This kind of picture can make a K look like a D.