What Causes To Have A Fish Eye Effect in Diamond?


The “Cut” of a diamond is believed to be the most important criterion for determining how beautiful a diamond looks and feels to the naked eye. Diamond cut depends on the proportions, symmetry, and polish that the cutter can design on to. This criterion hugely affects the brilliance, fire, and scintillation- overall the look and feel of the stone. This also means that if the job is not done precisely-the the stone would look low in terms of its luminosity and luster.

For understanding the cut of a diamond more thoroughly. Let us discuss some points, which are included in this specific case:



Also referred to as the sparkle of the diamond, this term means how brilliantly the stone sparkles and reflects light. When it is moved around a specific light source. The more well cut and precise the facets, the better the scintillation of the diamond.



The intensity by which white light gets reflected through the crown of a diamond is referred to as its brilliance. It is the measure of the diamond’s overall beauty.



It is also known by another term “fire”, dispersion is the amount of light. That gets reflected out from the stone in the spectrum from the initial light source that refracts light inside.

Through constant innovations and scrutinizations, cutters have provided the jewelry industry with variations of diamond cut qualities. Most of these variations are done by changing the shape, size, and cuts of the facets of the stones. The more precise and polished cut quality, the more is the sparkle of the diamonds.

Previously done by hand and some special cutting instruments. The diamonds used to have various flaws in their shapes and facets cuts. In the modern era- science has provided mankind with extensive technologies like computer-aided design and laser-cutting. Which has enabled us to create diamonds that are almost flawless in terms of both their cut quality and look and feel.

The Popularity of Some Specific Diamond Cuts


As mentioned earlier, there are different variants to the types of cuts and shapes that are available in the market. Among all the cut present, the most popular one is the round brilliant diamond cut. Which showcases the best proportionality and symmetry in terms of their facet arrangement. No other diamond sparkles as brilliantly as the round brilliant cut does. But premium things come with premium pricing as well. That is why there are other alternatives to the round brilliant cut available in the markets. Which are cost-efficient, good looking, and shiny enough. Moreover, these alternative cuts come with different types of shapes, like those of the pear and radiant cuts. Which look trendy according to the modern era of fashion.

The Fish Eye Effect in Diamond


Diamonds though being the perfect examples of beauty as they are are not always perfect in terms of their inclusions and flaws. Most of these stones showcase some degree of flaw or abnormalities in them. These inclusions maybe something related to the shape of the stone or the cut proportion of the stone or; something within the contents of the stone itself. 

With the above-mentioned term “Fish Eye” one must be thinking what fishes have to do with a diamond or are diamonds related to the fishes and the sea in any way. Well, we will be discussing it in a broader sense. But if one has purchased a diamond which has been said to contain the fish eye effect in diamond, one must understand that this is nothing to brag about and the buyer has made a mistake by purchasing such a stone.

Simply speaking, the Fish Eye effect in diamond is a type of inclusion in a diamond that happens due to some errors in the cut ratios of the stone.

Broadly speaking; if a diamond is cut too shallow, the table facet of the diamond shows the internal reflections of the girdle. The resultant is a grey ring type or spot formation which is very unpleasant to look at and which diminishes the look and sparkle factor of the diamond. This particular spot resembles the eyes of a fish and therefore the name “Fish Eye”.

To be frank, It does not matter if the same diamond which has the fisheye is graded with the highest color or clarity markings or and other attributes to its grading report. Such stones simply lack in terms of their brilliance and are not good looking at all.

How Do Fish Eye Effect in Diamond Form?

Let us discuss in a little depth about the factors which lead to the formation of the fish eye effect in diamond. The effect generally depends on the factors mentioned below:

  • Large size of the Table Facet,
  • Shallow pavilion angles, and
  • Thickness of the Girdle.


Due to the light travels, if the pavilion angles of a diamond are low then the diamond will naturally have lesser brilliance and will pronounce the cut defects that are included in the stone. Now when light enters the stone, the shallow depth of the stone causes the rays to be reflected through the table from the girdle portion. This also means that if a stone has a larger table facet and a thicker girdle, the fisheye effect of such a stone would be even more severe.

Do Shaped Diamonds Showcase Fish Eye Effect?


Technically speaking, fish eye effect is present in every such stone which has shallow pavilion angles and large table facets. It does not matter if the diamond is normal and round or if it is of any fancy shape. Hence, yes, fish eye effects do exist in fancy shaped diamonds like the pear, hearts, and ovals too.

Can Such Errors Be Recognized And Avoided?


Yes, absolutely. These kinds of flaws do not require any expert supervision and are pretty recognizable to the naked eye. The best suggestion would be to avoid such kind of diamonds by examining every diamond one looks for to purchase.

Another good suggestion would be to prioritize the cut quality, i.e. the degree of precision to which the diamond cut has been done. One should look at every video of the particular diamonds during the process of selection and should always keep a sound and stern mind to look for any form of errors there might be.

Buying a perfect diamond for the loved ones is not a joke, given the fact that these are not some cheap gifts that one gives as gifts daily. Diamonds are a whole emotion themselves and hence should always be checked by one for the best possible quality; free from any kind of flaws and errors.