There are basically 3 types of girdle finishing diamonds can come in: faceted, polished and bruted. Interestingly, the type of girdle finishing theoretically has no effect on the brilliance of a stone. If you had read up our entire section on cut, you would know that brilliance is largely determined by the proportions of the stone (e.g. pavilion angles, crown angles…).
Just a few decades ago, almost all round brilliant cuts have a bruted girdle because of the way diamonds were cut. This frosty appearance is created when a rough stone is rounded against another rough stone in a process called bruting.
In severe cases of the bruting process, a “bearded girdle” can form and the diamond’s surface resembles the appearance of a man’s beard. On a micro-scale level, the bearded girdle has many tiny feathers which give the diamond an opaque and frosty appearance. In badly worked diamonds, the feathers can extend into the diamond’s body and become marked as inclusions.
I would go on the record to say this: having a bruted girdle is no reason for joy. I don’t like the idea of an unfinished girdle and it represents sloppiness in the cutter’s workmanship. Bearded girdles should also be avoided due to the numerous “miniature cracks” around the diamond. This is because there is a likelihood of them growing into larger ones should there be accidental impacts.
For polished girdles, it means the entire girdle is polished into a single large and clear facet which enables you to see through into the diamond’s body.
The most common type of finishing found in modern day diamonds is the faceted girdle. Basically, a series of very small facets are made around the entire circumference and this faceting process removes tiny feathers caused during the bruting process.
Did you know that GIA only evaluates the thickness of the girdle and not the appearance of it? The reason why diamond cutters put in additional time and effort for girdle finishing is purely based on the notion that more consumers prefer it.
Personally, I prefer a faceted girdle as it gives me a cleaner and more complete look to the diamond. My wife wears a heart shaped diamond with a slightly thick – thick faceted girdle. Mounted in a prong basket setting, the diamond is set pretty high and exposes more areas of the stone to light. With casual observation from the side of the ring, you can sometimes see light returning off the girdle due to the presence of the tiny facets. To me, that is an added benefit of having faceted girdles.
If a diamond you like happens to have a bruted girdle, I personally feel that it would be a deal breaker. Come’on, it’s currently the 21st century and modern machining equipment is easily available anywhere in the world. There is no excuse for a cutter not to touch up the girdle for a more presentable look. Having either a polished or a faceted girdle would be OK but leaving a bruted girdle on a finished product is a sign of sloppiness I don’t cordon.