What is a fish eye diamond ? April 24, 2014 – Posted in: Wedding Rings
What Is A Fish Eye Diamond ?
When buying a diamond there are many factors to be taken into account. We have mentioned in our world of diamonds section on our website about the 4c’s and other variables that may be seen in your diamond. see https://loyesdiamonds.ie/the-four-cs
One easily spotted unpleasant feature that may be spotted in a badly cut diamond is a fish eye. What is a fish eye in a diamond?
A fish eye is a reflection of light just inside the table of the girdle on the opposing side. This phenomenon usually occurs only in shallow cut round diamonds. Technically the stone’s pavilion angle situated somewhere between 39 and 41 degrees and proportionally the table percentage is between 58.4% and 72.2%.
What this means is the diamond is too shallow and the table is too large. The girdle’s thickness and polish grade can also seriously vary the severity of the optical errors in the diamond.
Diamonds that present the fish eye effect are rated negatively in terms of their clarity and thus it is treated in effect like an inclusion, because that is how it appears to the naked eye.
At Loyes Diamonds our advise is you should never buy a diamond with a fish eye. The mere presence of a fish eye is instruction that the diamond has been severely cut in a very poor manner and will not perform by correctly. That is to say it will not refract the light in the correct manner and thus will lack all sparkle fire and scintillation.
Diamonds affected with fisheye have very cheap carat price compared to otherwise similar, unaffected stones hence you may see a diamond for sale at a considerably reduced price.
If you are on a tight budget but looking for a large stone and are not bothered by its optical performance then buying a stone with a slight case of fisheye might be just the thing you are looking for.
Unfortunately if this is the case Loyes Diamonds does not sell anything other then excellent cut to very good cut diamonds. All of our stones are certified to the highest standards and pass through the hands of at least 3 diamond graders before we examine each stone millimeter by millimeter to ensure that only the finest diamonds make it into our diamond engagement rings and diamond jewellery.