Inclusions & Blemishes

Diamond internal graining shown on GIA certificate

Internal graining as represented on GIA certificate

By now we hope that you are knee-deep in our diamond inclusions series! Our aim here is to make sure that you are so informed about buying diamonds, that when you talk to your friends about it they are annoyed with your depth of knowledge. If you feel like you are not yet at the ‘annoyingly informed’ level of diamond know-how, we suggest you go back to the beginning of our diamond inclusion series here.

What is Internal Graining?

So, you want to learn about internal graining? Excellent. ‘Internal Graining’ is exactly what it sounds like, pretty much. It happens when the crystal particles within the diamond have grown unevenly (i.e. some faster than others, in a sort of pattern). The result is what can be described as lines or waves that weave through the inside of the diamond itself, kind of like tracks left behind in the snow.

The lines or waves caused by internal graining do not all look the same. Some of them can be whitish, others more reflective.

A round diamond against a white background with two red arrows and a red circle highlighting lines in the diamond called internal graining

The bad news is that these lines and waves (or ‘grain center’ crystal distortions) cannot be removed because they are situated inside the diamond itself. The good news however, is that these are relatively rare, and if they sit in the right place, can have little impact on the overall look of the diamond.

If, for example, the graining was only visible through the pavilion (meaning the diamond had to be sitting on its side for you to see it) then it wouldn’t be too much of an issue. However if the internal graining/grain center was sitting right up on the table, then you might be in for a nasty surprise with that stone.

In order to avoid any issues we suggest that you consult with a qualified gemologist if you find evidence of ‘internal graining’ or ‘grain center’ on your desired stone. They'll take a look at the 10x magnification images and videos of the stone – along with the diamond grading report of course, and from there you can be advised as to whether you should jump on that diamond bandwagon or run for the hills. Our gemologists on instant chat are great at answering these questions and more! Hit us up.

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