What are surface grains?

[nu]

Can someone please explain what surface grains on a diamond are.

Thank you

 

[JohnQuixote]

Nothing to worry about.

Many times the grading report will list surface graining, pinpoints, additional clouds, etc. as 'not shown.' They are just noting that these things exist for sake of thoroughness. 'Not shown' means they are non-issues.

Surface graining is just structural irregularity. You can see it with a microscope. The graining may resemble faint facet junction lines, or cause a grooved or wavy surface. They look like polishing lines, but they often cross facet junctions (polishing lines don't). It is a natural characteristic of the diamond crystal and not a reflection of the cut quality.