What does it mean?
Many times a diamond grading report will list surface graining, pinpoints, additional clouds, etc. as 'not shown.' The diamond's report is just noting that these things exist for sake of thoroughness. 'Not shown' means they are non-issues.
Surface Graining is diamond structural irregularity. You can see it with a microscope. The diamond 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 where polishing lines don't. It is a natural characteristic of the diamond crystal, and not a reflection of the diamond's cut quality.
Pinpointing are miniscule spots internal to a Diamond. A diamond's cluster of pinpoints can form a cloud. To draw them would make them appear far more intense than they actually are, and would give a false impression of the diamond's clarity grade. For the sake of thoroughness Additional Clouds are mentioned, since they were taken into consideration for the diamond's total clarity grade. Not drawing them is standard procedure and nothing to worry about.
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