I would have thought it was a YG, it's certainly not a blue. There are however, variables to take into account with ebay pictures, namely screen resolution, and the lighting present when the picture was taken; lapping could vary the shade even further.

In any case, it is a genuine Escher which is my favourite finisher. I love this stone, and yes, it may be used after a coticule despite certain literature which suggests it may not improve the edge after one. I use it after my 8K Naniwa.

I'd be interested to read your experience with the Escher, so be sure to post!