Surface graining?

[Wfpajfad]

Hi..

I was looking at the certificate for my diamond and it has "surface graining" in the comments part.

What does this mean?

Thanks

 

[Grishadiam]

graining can sometimes be polished off the stone.

it is very difficult to see under a x10 magnification loupe you really need a microscope to be able to see graining in a stone.