(I have stored up so many questions - I am really glad to have a venue for asking them now!)  Okay, What does it mean when a GIA notes: surface graining is not shown?

If you are considering a stone with that remark on the report, I really think you should talk to David.

For the curious among us that cannot eavesdrop on the conversation, surface graining is when the stone shows crystal grain lines on the surface (doh!). This picture may make it easier to visualise:



These are effectively diamond crystal growth edges - and are a real beast to polish, because the surface tends to slough off (technical term) in layers that repeat the grain pattern. "Not shown" means the location of the graining lines is not marked on the plot. As David says, it may be no problem, if they are not shown because the area with the grain is minimal and hardly noticeable without strong magnification (the photo above is ~x100). If on the other hand they are not shown because the whole stone - or even just the table - is covered in grain lines, and showing them would compromise the readability of the plot, it can be distinctly bad news.

Me, neither, saqsay1.    I had no idea.  Good question, BTW, ANF! 

Very interesting info, OMC.  Guess that's one of the side benefits of buying from DBL.  Just one of those tricksy little items you don't have to worry about!