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Inclusions & Blemishes

Diamond Blemishes: Surface Graining



·1 min read

Surface graining shown on a GIA certificate

You’re (about to be) engaged! YAY! In order to get you on that path to victory, we want to make sure that you take a look back at all of our previous blog posts, especially those relating to diamond inclusions. There’s a wealth of information there to get you on track. We suggest you begin with our intro on diamond imperfections before you hurl head-first into something like surface graining, as it will give you a nice bit of foundational knowledge for you to sink your teeth into. Click here for that intro.

What is Surface Graining?

When discussing surface graining, it’s important to point out that unlike some of our other blemishes (I’m looking at you burn marks), surface graining is not actually the result of some dodgy diamond polish job. Instead, it is a natural occurrence and the result of the diamond crystal itself; some areas growing faster than others, for instance. 

Surface graining can look a little like polish lines or streaks on a window - but unfortunately, unlike polish lines, they cannot be removed with a re-polish! This is because they are part of the crystal’s natural structure (rather than human error like polish lines/burn marks etc.). Here’s an example of those streaky offenders.

Round diamond against a white background with two circles around lines on the diamond called "surface graining"

Not only are they a permanent and often unsightly fixture, but they can also impact the clarity of the stone in a bad way. That’s because all those nasty streaks are impeding the light from getting in and bouncing around inside that diamond (which is what makes the whole thing sparkle in the first place). Less light means the diamond can appear lifeless, which is the opposite of the goal.

Dr. Rian Mulcahy
Rian is officially a Diamond PhD - just ping us if you’d like to read her fascinating 200-page thesis, titled Facets of Value: An Investigation into the Formation of Worth in the Diamond Market. She has consulted various firms all along the pipeline, from the rough diamond market to the recycled diamond industry. She holds an MA in Globalisation and Development from University College Cork and a PhD in the Sociology of Diamond Valuation from the London School of Economics.