Internal and Surface Graining

[bluedevil27]

What is internal and surface graining? In the comments section of a cert I am looking at it says "internal graining and surface graining not shown". I''m not familiar with these types of inclusions? Are they bad?

Thanks

 

[CaptAubrey]

It''s neither bad nor anything to be concerned about. It''s not shown on the clarity plot because doing so would make the diamond look a lot worse than it is.

Graining is the result of various sorts of "hiccups" in the diamond''s crystal structure, which is to say that in certain places in this diamond, the carbon atoms are not lined up in the ideal tetrahedral diamond arrangement. These defects interfere with the transmission of light through the stone, but only in very subtle ways. Among other things, graining can cause the appearance of fine lines on the surface or vague, hazy areas in the stone. However, in most cases, you need a microscope and professional tranining to even see these things. Only in very rare cases do you have graining that is strong enough to create eye-visible effects, and only with high-clarity stones (IF, VVS) is graining going to be an issue for the clarity grade.

The wording on that report means that the grader saw it during examination but that it wasn''t a grade-setting characteristic. So it''s nothing to worry about here.

 

[bluedevil27]

Thanks for your feedback!

 

[Lorelei]

Date: 1/17/2008 3:24:57 PM
Author: CaptAubrey
It''s neither bad nor anything to be concerned about. It''s not shown on the clarity plot because doing so would make the diamond look a lot worse than it is.

Graining is the result of various sorts of ''hiccups'' in the diamond''s crystal structure, which is to say that in certain places in this diamond, the carbon atoms are not lined up in the ideal tetrahedral diamond arrangement. These defects interfere with the transmission of light through the stone, but only in very subtle ways. Among other things, graining can cause the appearance of fine lines on the surface or vague, hazy areas in the stone. However, in most cases, you need a microscope and professional tranining to even see these things. Only in very rare cases do you have graining that is strong enough to create eye-visible effects, and only with high-clarity stones (IF, VVS) is graining going to be an issue for the clarity grade.

The wording on that report means that the grader saw it during examination but that it wasn''t a grade-setting characteristic. So it''s nothing to worry about here.

Ditto and these are very commonly seen remarks on GIA grading reports, no worries!