Other Consequences of Poor Cut Proportions

Tables that Appear Very Dark

If purchasing a diamond be on the lookout for a table that appears very dark. This is a result of the pavilion of the diamond being cut too deep.

This effect is called the "Nailhead" effect. A "Nailhead" diamond is not a pretty sight and should be avoided at all cost.

Tables That Show the "Fisheye" Effect

When buying diamonds, we should also be on the lookout for "glassy", 'hollow-looking' diamonds that show a circular rim similar to a "fisheye" appearance just within the table of the diamond. The diamond will show this effect as a result of the pavilion being cut too shallow.

The circular rim as actually the reflection of the girdle appearing through the table because of the poorly cut pavilion.

Obviously, the "fisheye" is unsightly and should be avoided.

Girdle Faults to Note

Ideally, a diamond's girdle should be of medium thickness. The girdle is that portion of the diamond which is usually grasped by the claws or the mount in order that it is firmly held in place. We should avoid a very thin or extremely thin ('knife-edge') tirdle as this may result in a diamond that can easily break and chip around the girdle. A thin girdle (about 1.2% around the valley) should be acceptable, but we should worry if it is anything less than that. On the other hand, a very thick girdle is unsightly and adds unnecessary weight to the diamond.

A diamond with polished girdle is preferred because it looks better.

We should also avoid diamonds with excessive bearding. Bearding refers to numerous small fractures that extend into the diamond from the girdle. This is a result of the diamond cutter 'rounding' the girdle up too quickly.

The Culet

The culet (or tip) of the diamond should come to a small point. There is no reason to accept a diamond with a large culet (known as a 'well') because it is unsightly, and light can be lost through it. We should make sure that the diamond is small (1.5%) at most.

Most ideal cut diamonds these days do not have a culet. The diamond simply ends with a sharp point. While this may increase the risk of the point chipping off, the risk is usually non-existent once the diamond is mounted in its setting.

When buying diamonds, we should also avoid culets that are chipped and abraded.

The Good News

The good news for consumers nowadays is that none of the above problems exist if the diamond is graded as GIA Excellent or AGS Ideal for cut. If you get a diamond with a corresponding report, you can rely on it.

However, if you get an uncertified diamond, you will have to rely on a qualified gemologist to check it for you.

Up Next... The Ideal Cut Diamond!

If you have gone through the articles digilently up to this point, you would have quite a wealth of knowledge already. Next, we can make use of our knowledge and pick out the ideal cut diamond we prefer.

We shall discuss how experts determine what constitutes an ideal cut diamond over the next few pages.